Simplification (Railway Maths) (501 to 550)

Total Questions: 50

21. If √(15 × 27 × x) = 180, then x is equal to: [RRB NTPC 23/02/2021 (Morning)]

Correct Answer: (c) 80
Solution:

√(15 × 27 × x) = 180
⇒ 15 × 27 × x = 180 × 180
⇒ x = (180 × 180) / (15 × 27)
⇒ x = 80

22. If √0.03 × 0.3 × p = 0.3 × 0.03 × √q, then p/q is: [RRB NTPC 27/02/2021 (Morning)]

Correct Answer: (b) 0.009
Solution:

√0.03 × 0.3 × p = 0.3 × 0.03 × √q
⇒ √0.009 × p = 0.009 × √q
⇒ √0.009 × √p = 0.009 × √q
Squaring both sides
⇒ 0.009 × p = 0.009 × 0.009 × q
⇒ p / q = 0.009

23. The value of (0.3)⁴ − (0.2)⁴ / (0.3)² + (0.2)² is: [RRB NTPC 27/02/2021 (Morning)]

Correct Answer: (a) 0.05
Solution:

24. Find the value of [RRB NTPC 27/02/2021 (Evening)]

1/(2 × 4) + 1/(4 × 6) + 1/(6 × 8) + …… + 1/(48 × 50)

Correct Answer: (d) 0.24
Solution:

25. If 0.17 ÷ p²= 17, then the value of p is: [RRB NTPC 27/02/2021 (Evening)]

Correct Answer: (c) 0.1
Solution:

0.17 ÷ p² = 17
0.17 × (1 / p²) = 17
⇒ p = 0.1

26. Find the value of [RRB NTPC 01/03/2021 (Morning)]

(19 × 9 + 31 × 10 + 32 × 11) / (233.25 × 2 − 50)

Correct Answer: (a) 2
Solution:

(19 × 9 + 31 × 10 + 32 × 11) / (233.25 × 2 − 50)
= (171 + 310 + 352) / (466.5 − 50)
= 833 / 416.5
= 2

27. If (5 + 2√3) / (2 − √3) = x + y√3, then (x, y) = ? [RRB NTPC 01/03/2021 (Morning)]

Correct Answer: (d) (16, 9)
Solution:

28. Find the answer of given equation? [RRB NTPC 01/03/2021 (Evening) ]

Correct Answer: (b) -13/16
Solution:

29. Find the value of x. [RRB NTPC 01/03/2021 (Evening) ]

(17)³ + 7³ / (17)² + 7² - x = 24

Correct Answer: (c) x = 119
Solution:

30. Find the positive value of the following square root [RRB NTPC 02/03/2021 (Morning) ]

Correct Answer: (b) 8
Solution: