Exercise : 4


1. What should come in place of the question mark (?) in the following equation?

5679 + 1438 – 2015 = ?

(a) 5192
(b) 5012
(c) 5102
(d) 5002
(e) None of these
Ans.c

? = 5679 + 1438 – 2015 = 5102

2. What should come in place of the question mark (‘?) in the following equation?

1825 of 150.8 + ? = 8697.32 – 3058.16

(a) 2764.44
(b) 2864.34
(c) 1864.44
(d) 2684.44
(e) None of these
Ans.e

? = 8697.32 – 3058.16 – 925 × 150.8

= 5639.16 – 2774.72 = 2864.44

3. What should come in place of the question mark in the following questions?

?24 = 72√?

(a) 12
(b) 16
(c) 114
(d) 144
(e) None of these
Ans.d

? × √? = 24 × 72 Squaring both the sides,

(?2 × ? ) = ?3 = (8 × (3) × (8 × 3) × (8 × 9) × (8 × 9)

= 238393

∴ ? = 2 × 8 × 9 = 144

4. What should come in place of the question mark (?) in the following equation?

656 × 513 + 1723 × 12 = ?

(a) 11213
(b) 663
(c) 240
(d) 11623
(e) None of these
Ans.e

? = 416 × 163 + 533 × 92 = \(\frac{41 \times 16 + 53 \times 9 \times 3}{6 \times 3}\)

= \(\frac{656 + 1431}{18} = \frac{2087}{18} = 115\tfrac{17}{18}\)

5. What approximate value should come in place of the question mark (?) in the following equation?

35% of 1478 + 29% of 3214 = ?

(a) 1600
(b) 1250
(c) 1300
(d) 1450
(e) 1500
Ans.d

? = 35% of 1478 + 29% of 3214

≈ 35% of (1500 – 22) + (30% – 1%) of 3200

≈ 35 × 15 – 8 + 30 × 32 – 32

= 525 + 960 – 40 = 525 + 920

= 1445 ≈ 1450

6. What approximate value should come in place of the question mark (?) in the following equation ?

57 of 1596 + 3015 = ? – 2150

(a) 7200
(b) 48000
(c) 5300
(d) 58000
(e) 6300
Ans.e

? ≈ 5 × 230 + 3000 + 2150

= 1150 + 3000 + 2150 = 6300

7. In the following equation what value would come in place of question mark (?)?

5798 – ? = 7385 – 4632

(a) 3225
(b) 2595
(c) 2775
(d) 3045
(e) None of these above
Ans.d

? = 5798 + 4632 – 7385 = 3045

8. What approximate value should come in place of the question mark (?) in the following equation?

152√? + 795 = 8226 – 3486

(a) 425
(b) 985
(c) 1225
(d) 1025
(e) 675
Ans.e

152√? ≈ 8200 - 3500 - 800 = 3900

∴ √? = 3900152

= slightly less than (4000150) = 26.67 i.e., 26

∴ √? = (26)2 = 676 ≈ 675

9. What approximate value should come in place of the question mark(?) in the following equation?

6.39 × 15.266 + 115.8 of 25 = ?

(a) 145
(b) 165
(c) 180
(d) 130
(e) 135
Ans.a

? = 6.39 × 15.266 + 115.8 of 25

≈ 6.50 × 15 + 115 × 0.4 = 97.50 + 46 ≈ 145

10. What should come in place of question mark(?) in the following equation?

8597 – ? = 7429 – 4358

(a) 5706
(b) 5526
(c) 5426
(d) 5626
(e) None of these
Ans.b

8597 – ? = 7429 – 4358

∴ ? = 5526