RRB Group Maths Questions Quiz 4 with Explanation

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Direction : Study the following questions carefully and choose the right answer.
Important for :
1
What value should come in place of question mark.

[17.98 ÷ 6.2] + [1.25 ÷ 0.5] – [0.96 ÷ 0.8] = ?
» Explain it
A
⇒ ? = 17.98  +  1.25  –  0.96
6.2 0.5 0.8

⇒ ? = 2.9 + 2.5 – 1.2

⇒ ? = 5.4 – 1.2

∴ ? = 4.2

Hence, option A is correct.
 
2
The age of Sitamma 10 years ago was thrice the age of Radha. 10 years hence, Sitamma’s age will be twice that of Radha. What is the ratio of their present age?
» Explain it
A
Let the present ages of Sitamma and Radha are x and y years respectively.

We have,

10 years ago age of Sitamma was 3 times the age of Radha.

i.e. (x – 10) = 3 (y – 10)

⇒ 3y – x = 20 .............(i)

And,

10 years later age of Sitamma will be twice the age of Radha.

i.e. (x + 10) = 2 (y + 10)

⇒ x – 2y = 10 .............(ii)

Adding eqn. (i) and (ii), we get

y = 30 years

Put y = 30 years in eqn. (i), we get

⇒ 3 × 30 – x = 20

⇒ 90 – 20 = x

∴ x = 70 years

Required Ration = x : y

= 70 : 30 or, 7 : 3

Hence, option A is correct.

3
What value shoule come in place of question mark

1 2  + 2 1  + 2 2  – 4 1  = ?
3 3 3 2
» Explain it
C
1 2  + 2 1  + 2 2  – 4 1  = ?
3 3 3 2

⇒ ? =  5  +  7  +  8  –  9
3 3 3 2

⇒ ? =  5 + 7 + 8  –  9
3 12

⇒ ? =  20  –  9
3 12

⇒ ? =  40 – 27
6

⇒ ? =  13
6

∴ ? = 2 1
6

Hence, option C is correct.

4
What value should come in place of question mark.

67. 436 × 17 × 3 ÷ 32 = ?
» Explain it
B
⇒ ? =  436 × 17 × 3
32

⇒ ? =  22236
32

∴ ? = 694.876

Hence, option B is correct.
 
5
The average attendance of a college for the first three days of a week is 325 and first four days is 320. How many were present on the fourth day?
» Explain it
D
Average attendance for first three days = 325

Total attendance for first three days = 325 × 3 = 975

Average attendance for first four days = 320

Total attendance for first four days = 1280

Attendance on fourth day = 1280 – 975 = 305

Hence, option D is correct.