Page 231 - Maths Skills - 7

Answers 229

13. 1 part = ` 1500, 2 part = ` 1000 14. ` 676.50
nd
st
1 1
15. (i) ` 121.50, ` 931.50 (ii) ` 55, ` 555 (iii) ` 375, ` 465 (iv) 1 years, ` 890 (v) 8 %, ` 1530
2 2
Assessment Time
A. 1. (iii) 2. (i) 3. (ii) 4. (iii) 5. (iv)
B. 1. ` 90 2. 3.125 g 3. ` 1575 4. 45% 5. Selling price
C. 1. T 2. F 3. T 4. T 5. T
D. 1. 12% 2. 63000 3. 20% 4. 65000 E. 1. (a) 2. (b) 3. (a)
F. 1. Sunita performance is better as she scored 89.33% whereas Amar got 84%. 2. 35% 3. ` 207
3
4. ` 9450, Present increase in salary = ` 450 5. 378 eggs G. 1. (a) (b) 60
10
(c) Yes, there is an increment (20 students). Increase = 12.5% (d) Football = 72 chess = 144 cricket = 180 Hockey = 60

HOTS
1
1. ` 5,176.47 2. ` 4,000 3. 22% 4. 9 %
11
Chapter - 6: Exponents and Powers
Boot-up

A. 1. (iv) 2. (ii) 3. (iii) 4. (iii) B. 1. 216 or 6 × 6 × 6 2. multiplication 3. Power 4. 5x
C. 1. T 2. F 3. F 4. T

Exercise - 6.1
6
3
1. (i) (–7) (ii) (5) (iii) (–104) (iv) (–7) 1
11
2. (i) (ii) (iii) (iv) (v) (vi)
Base 8 9/3 8.25 –7 0.01 –1
Exponent 14 2 5 7 1 16
3. (i) 4000 (ii) 361 (iii) –243 (iv) 1 (v) 7203 (vi) –1728 (vii) 32768 (viii) 1

 3  4 1
4. (i)   (ii) (–11) (iii) (2) 5. (i) (ii) – 729 (iii) 0 (iv) 625 6. (i) x = 6 (ii) x = 7 (iii) x = 4
10
3
 4  256
Exercise - 6.2
−1
1. (i) –27 (ii) (iii) x (iv) 16 (v) 1 (vi) 144 (vii) 1 (viii) (–b) p–q
8 7 5
7 
−
4
2. (i) 2 8 (ii) 8 5 (iii) a 11 (iv)    (v) (–9) (vi) (x) p+q (vii)  1   (viii) (a) m+3

 5   5 
3. (i) (pq) (ii) 6 8 (iii) (ab) (iv) 14 (v) 8 (vi) (15) a (vii) a 2m (viii) (5a) 3
x
9
x
m
9
4. (i) 2744 (ii) 20736 (iii) 1728 (iv) (v) (ab) (vi) – 64 5. (i) (6) (ii) (–3) 6
x
4
49
6 8
 1   1  9
2a
mn
(iii)   (iv) (10) 12 (v)  −  (vi) (x) (vii) (b) (viii) (–2) 3x 6. (i) (ii) 8
 5   3  16
Exercise - 6.3
1. (i) 3.0 × 10 m/s (ii) 1 × 10 (iii) 8.6 × 10 g (iv) 1.496 × 10 m (v) 4.8 × 10 (vi) 1.73448 × 10 s
11
28
9
–9
8
11
2. (i) 1.8 × 10 (ii) 2.45 × 10 (iii) 1.63 × 10 (iv) 8.93256 × 10 2 3. (i) 62,073 (ii) 98,76,543
10
10
8
(iii) 3,01,02,06,049 4. (i) 8,50,00,000 (ii) 6,073 (iii) 27,00,000 (iv) 33,300
Assessment Time
−1
A. 1. (iii) 2. (iv) 3. (ii) 4. (ii) 5. (iii) B. 1. 2 15 2. 13 3.
343
4. 2 5. 7 × 10 bytes C. 1. F 2. T 3. T 4. T 5. T
6
D. (i) 1 × 10 (ii) 1.87 × 10 (iii) 9 × 10 (iv) 9.82 × 10 E. 1. (a) 2. (a) 3. (a) F. 1. 4
13
7
12
–5
9abc
72 21
2. 7 3. 96 cm 4.
1000