Simplification (Railway Maths) (651 to 700)

Total Questions: 50

1. What is the value of x in the following equation ? [RRB NTPC 08/04/2021 (Evening) ]

3²ˣ ⁺ ¹ - 3ˣ =  3ˣ ⁺ ³ - 3²

Correct Answer: (c) 2, -1
Solution:

2. How much does one have to subtract from 8/5 to obtain 5/8 ? [RRB NTPC 23/07/2021 (Morning)]

Correct Answer: (b) 39/40
Solution:

8/5 − 5/8 = (64 − 25) / 40 = 39/40

3. If 4x − 3y = 9 and x = 6, then what is the value of y ? [RRB NTPC 23/07/2021 (Morning)]

Correct Answer: (c) 5
Solution:

Put x = 6
⇒ 4 × 6 − 3y = 9 ⇒ 24 − 3y = 9
⇒ 3y = 24 − 9 = 15 ⇒ y = 5

4. Express −40/56 as a rational number whose numerator is −5. [RRB NTPC 23/07/2021 (Evening)]

Correct Answer: (b) −5/7
Solution:

−40/56
Divide numerator and denominator by 8,
we get ⇒ −5/7

5. If c/d = 1 ÷ 3/4, then c + d / c - d = ? [RRB NTPC 23/07/2021 (Evening) ]

Correct Answer: (c) 7
Solution:

c/d = 1 ÷ 3/4 ⇒ c/d = 4/3
Now,
c + d / c - d = 4 + 3 / 4 - 3 = 7

6. Answer the following question? [RRB NTPC 23/07/2021 (Evening) ]

Correct Answer: (b) 2/3
Solution:

7. If (2/3)ˣ ⁺ ¹ = (3/2)ˣ ⁻ ¹ then x = ? [RRB NTPC 24/07/2021 (Morning) ]

Correct Answer: (c) 0
Solution:

8. The cube root of 250 lies between: [RRB NTPC 24/07/2021 (Morning) ]

Correct Answer: (d) 6 and 7
Solution:

∛250 is lie between 6 and 7
6³ = 216 and 7³ = 343

9. The value of √0.0121 + ³√0.008 is: [RRB NTPC 24/07/2021 (Morning) ]

Correct Answer: (b) 0.31
Solution:

√0.0121 + ∛0.008
0.11 + 0.2 = 0.31

10. What is the value of (0.03) × (0.05) × (1.5) / 0.0225 ? [RRB NTPC 24/07/2021 (Morning) ]

Correct Answer: (b) 0.1
Solution: