Brain Grain · braingrain.in
Maths — Practice Paper · Set 1
Part I — Short Answer Questions 12 × 2 = 24
Answer briefly. (Answer all questions.)
1.Exercise 7.1 asks students to convert fractions and decimals to percentages, convert percentages to fractions or decimals, find percentages of quantities, find whole quantities from percentages, compare percentages and solve percentage word problems.[2]
2.Exercise 11.2 asks students to simplify expressions using laws of exponents, say true or false with justification, express products in prime-factor exponential form and simplify expressions involving powers and variables.[2]
3.1. Find: (i) $12\div\frac{3}{4}$[2]
4.1. Set up equations and solve them to find the unknown numbers in statements (a) to (g). 2. Solve the word problems on lowest score, equal angles, and runs scored by Sachin and Rahul. 3. Solve the given age and number problems. 4. Solve the perimeter problem in the exercise.[2]
5.Exercise 11.1 asks students to evaluate powers, express repeated products in exponential form, write numbers as powers, express numbers as products of prime factors in exponential form, simplify expressions using powers, evaluate powers with negative bases and compare large numbers written in standard form.[2]
6.Exercise 8.2 asks students to add, subtract, multiply and divide rational numbers in the listed subparts.[2]
7.1. Find: (i) $0.2\times6$[2]
8.Exercise 10.2 asks students to add and subtract algebraic expressions, simplify expressions, evaluate simplified expressions for given variable values, and solve a perimeter/algebraic-expression problem.[2]
9.1. Give first the step you will use to separate the variable and then solve the equation. 2. Give the steps you will use to separate the variable and then solve the equation. 3. Solve the equations given in paired form. 4. Solve the listed simple equations involving $p,s,q$[2]
10.1. Find: (i) $0.4\div2$[2]
11.Exercise 7.2 asks questions on profit, loss, profit percentage, loss percentage, discount, sales tax, simple interest, amount and rate/time/principal word problems.[2]
12.1. Find each of the following products: (a) $3\times(-1)$[2]
🔑 Show Answer Key — Set 1
- 1. 1. (a) $12.5\%$ (b) $125\%$ (c) $7.5\%$ (d) $28\frac{4}{7}\%$ . 2. (a) $65\%$ (b) $210\%$ (c) $2\%$ (d) $1235\%$ . 3. (i) $25\%$ (ii) $\frac{3}{5};60\%$ (iii) $\frac{3}{8};37.5\%$ . 4. (a) 37.5 (b) $\frac{3}{5}$ minute or 36 seconds (c) Rs 500 (d) 0.75 kg or 750 g. 5. (a) 12000 (b) Rs 9000 (c) 1250 km (d) 20 minutes (e) 500 litres. 6. (a) $0.25;\frac{1}{4}$ (b) $1.5;\frac{3}{2}$ (c) $0.2;\frac{1}{5}$ (d) $0.05;\frac{1}{20}$ . 7. $30\%$ . 8. $40\%;6000$ . 9. Rs 40,000. 10. 5 matches.
- 2. 1. (i) $3^{14}$ (ii) $6^5$ (iii) $a^5$ (iv) $7^{x+2}$ (v) $5^3$ (vi) $10^5$ (vii) $(ab)^4$ (viii) $3^{12}$ (ix) $2^8$ (x) $8^{t-2}$ . 2. (i) $3^3$ (ii) $5^3$ (iii) $5^5$ (iv) $7\times11^5$ (v) $3^0$ or 1 (vi) 3 (vii) 1 (viii) 2 (ix) $(2a)^2$ (x) $a^{10}$ (xi) $a^3b$ (xii) $2^8$ . 3. (i) False; $10\times10^{11}=10^{12}$ and $(100)^{11}=10^{22}$ (ii) False; $2^3=8$ , $5^2=25$ (iii) False; $6^5=2^5\times3^5$ (iv) True; $3^0=1$ , $(1000)^0=1$ . 4. (i) $2^8\times3^4$ (ii) $2\times3^3\times5$ (iii) $3^6\times2^6$ (iv) $2^8\times3$ . 5. (i) 98 (ii) $\frac{4}{5t^8}$ (iii) 1.
- 3. 1. (i) 16 (ii) $\frac{84}{5}$ (iii) $\frac{24}{7}$ (iv) $\frac{3}{2}$ (v) $\frac{9}{7}$ (vi) $\frac{7}{5}$ . 2. (i) $\frac{7}{3}$ , improper fraction (ii) $\frac{8}{5}$ , improper fraction (iii) $\frac{7}{9}$ , proper fraction (iv) $\frac{5}{6}$ , proper fraction (v) $\frac{7}{12}$ , proper fraction (vi) $8$ , whole number (vii) $11$ , whole number. 3. (i) $\frac{2}{21}$ (ii) $\frac{5}{36}$ (iii) $\frac{7}{78}$ (iv) $\frac{5}{6}$ (v) $\frac{11}{14}$ (vi) $\frac{13}{14}$ . 4. (i) $\frac{4}{5}$ (ii) $\frac{2}{3}$ (iii) $\frac{3}{8}$ (iv) $\frac{35}{54}$ (v) $14$ (vi) $\frac{14}{5}$ (vii) $\frac{48}{25}$ (viii) $1$ .
- 4. 1. (a) $8x+4=60$ , $x=7$ (b) $\frac{x}{5}-4=3$ , $x=35$ (c) $\frac{3y}{4}+3=21$ , $y=24$ (d) $2m-11=15$ , $m=13$ (e) $50-3x=8$ , $x=14$ (f) $\frac{x+19}{5}=8$ , $x=21$ (g) $\frac{5n}{2}-7=23$ , $n=12$ . 2. (a) Lowest score $=40$ (b) $70^\circ$ each (c) Sachin: 132 runs, Rahul: 66 runs. 3. (i) 6 (ii) 15 years (iii) 25. 4. 30.
- 5. 1. (i) 64 (ii) 729 (iii) 121 (iv) 625. 2. (i) 64 (ii) $t^2$ (iii) $b^4$ (iv) $5^2\times7^3$ (v) $2^2\times a^2$ (vi) $a^3\times c^4\times d$ . 3. (i) $2^9$ (ii) $7^3$ (iii) $3^6$ (iv) $5^5$ . 4. (i) $3^4$ (ii) $3^5$ (iii) $2^8$ (iv) $2^{100}$ (v) $2^{10}$ . 5. (i) $2^3\times3^4$ (ii) $5\times3^4$ (iii) $2^2\times3^3\times5$ (iv) $2^4\times3^2\times5^2$ . 6. (i) 2000 (ii) 196 (iii) 40 (iv) 768 (v) 0 (vi) 675 (vii) 144 (viii) 90000. 7. (i) $-64$ (ii) 24 (iii) 225 (iv) 8000. 8. (i) $2.7\times10^{12}>1.5\times10^8$ (ii) $4\times10^{14}<3\times10^{17}$ .
- 6. 1. (i) $-\frac{3}{2}$ (ii) $\frac{34}{15}$ (iii) $\frac{17}{30}$ (iv) $\frac{82}{99}$ (v) $-\frac{26}{57}$ (vi) $-\frac{2}{3}$ (vii) $\frac{34}{15}$ . 2. (i) $-\frac{13}{72}$ (ii) $\frac{23}{63}$ (iii) $\frac{1}{195}$ (iv) $-\frac{89}{88}$ (v) $-\frac{73}{9}$ . 3. (i) $-\frac{63}{8}$ (ii) $-\frac{27}{10}$ (iii) $-\frac{54}{55}$ (iv) $-\frac{6}{35}$ (v) $\frac{6}{55}$ (vi) 1. 4. (i) $-6$ (ii) $-\frac{3}{10}$ (iii) $\frac{4}{15}$ (iv) $-\frac{1}{6}$ (v) $-\frac{14}{13}$ (vi) $\frac{91}{24}$ (vii) $-\frac{15}{4}$ .
- 7. 1. (i) 1.2 (ii) 36.8 (iii) 13.55 (iv) 80.4 (v) 0.35 (vi) 844.08 (vii) 1.72. 2. $17.1\text{ cm}^2$ . 3. (i) 13 (ii) 368 (iii) 1537 (iv) 1680.7 (v) 3110 (vi) 15610 (vii) 362 (viii) 4307 (ix) 5 (x) 0.8 (xi) 90 (xii) 30. 4. 553 km. 5. (i) 0.75 (ii) 5.17 (iii) 63.36 (iv) 4.03 (v) 0.025 (vi) 1.68 (vii) 0.0214 (viii) 10.5525 (ix) 1.0101 (x) 110.011.
- 8. 1. (i) 0 (ii) 1 (iii) $-1$ (iv) 1 (v) 1. 2. (i) $-1$ (ii) $-13$ (iii) 3. 3. (i) $-9$ (ii) 3 (iii) 0 (iv) 1. 4. (i) 8 (ii) 4 (iii) 0. 5. (i) $-2$ (ii) 2 (iii) 0 (iv) 2. 6. (i) $5x-13$ ; at $x=2$ , value $=-3$ (ii) $8x-1$ ; value $15$ (iii) $11x-10$ ; value $12$ (iv) $11x+7$ ; value $29$ . 7. (i) $2x+4$ ; 10 (ii) $-4x+6$ ; $-6$ (iii) $-5a+6$ ; 11 (iv) $-8b+6$ ; 22 (v) $3a-2b-9$ ; $-8$ . 8. (i) 1000 (ii) 20. 9. $-5$ . 10. $2a^2+ab+3$ ; value $38$ .
- 9. 1. (a) Add 1 to both sides; $x=1$ (b) Subtract 1 from both sides; $x=-1$ (c) Add 1 to both sides; $x=6$ (d) Subtract 6 from both sides; $x=-4$ (e) Add 4 to both sides; $y=-3$ (f) Add 4 to both sides; $y=8$ (g) Subtract 4 from both sides; $y=0$ (h) Subtract 4 from both sides; $y=-8$ . 2. (a) Divide both sides by 3; $l=14$ (b) Multiply both sides by 2; $b=12$ (c) Multiply both sides by 7; $p=28$ (d) Divide both sides by 4; $x=\frac{25}{4}$ (e) Divide both sides by 8; $y=\frac{36}{8}$ (f) Multiply both sides by 3; $z=\frac{15}{4}$ (g) Multiply both sides by 5; $a=\frac{7}{3}$ (h) Divide both sides by 20; $t=\frac{1}{2}$ . 3. (a) Add 2 to both sides, then divide by 3; $n=16$ . (b) Subtract 7…
- 10. 1. (i) 0.2 (ii) 0.07 (iii) 0.62 (iv) 10.9 (v) 162.8 (vi) 2.07 (vii) 0.99 (viii) 0.16. 2. (i) 0.48 (ii) 5.25 (iii) 0.07 (iv) 3.31 (v) 27.223 (vi) 0.056 (vii) 0.397. 3. (i) 0.027 (ii) 0.003 (iii) 0.0078 (iv) 4.326 (v) 0.236 (vi) 0.9853. 4. (i) 0.0079 (ii) 0.0263 (iii) 0.03853 (iv) 0.1289 (v) 0.0005. 5. (i) 2 (ii) 180 (iii) 6.5 (iv) 44.2 (v) 2 (vi) 31 (vii) 510 (viii) 27 (ix) 2.1. 6. 18 km.
- 11. 1. (a) Profit = Rs 75; Profit % = 30 (b) Profit = Rs 1500; Profit % = 12.5 (c) Profit = Rs 500; Profit % = 20 (d) Loss = Rs 100; Loss % = 40. 2. (a) $75\%;25\%$ (b) $20\%,30\%,50\%$ (c) $20\%;80\%$ (d) $12.5\%;25\%;62.5\%$ . 3. $2\%$ . 4. $5\frac{5}{7}\%$ . 5. Rs 12,000. 6. Rs 16,875. 7. (i) $12\%$ (ii) 25 g. 8. Rs 233.75. 9. (a) Rs 1,632 (b) Rs 8,625. 10. $0.25\%$ . 11. Rs 500.
- 12. 1. (a) $-3$ (b) $-225$ (c) $630$ (d) $316$ (e) $0$ (f) $1320$ (g) $162$ (h) $-360$ (i) $-24$ (j) $36$ . 2. (a) LHS $=18\times4=72$ and RHS $=126-54=72$ . (b) LHS $=(-21)\times(-10)=210$ and RHS $=84+126=210$ . 3. (i) $(-1)\times a=-a$ (ii) (a) $22$ (b) $-37$ (c) $0$ . 4. A pattern is $-1\times5=-5$ , $-1\times4=-4$ , $-1\times3=-3$ , $-1\times2=-2$ , $-1\times1=-1$ , $-1\times0=0$ , so continuing the pattern gives $-1\times(-1)=1$ .