Mixed Quantitative Aptitude Questions Set 232

1. The ratio of the milk to water in a mixture is 4 : 3. 21 liter of mixture is taken out and 8 liter of milk and 14 liter of water is added in mixture, so that new ratio of milk to water becomes 320 : 17, then find initial quantity of milk in the mixture ?
84 liters
35 liters
63 liters
80 liters
72 liters
Option A
Let quantity of milk and water in the mixture = 4x and 3x respectively
(4x – 21 * 4/7 + 8)/(3x – 21 * 3/7 + 14) = 20/17
4x – 4/3x + 5 = 20/17
x = 21
Initial quantity of milk in the mixture = 4x = 4 * 21 = 84 liters

2. A alone can do 40% of work in 8 days and B alone can do 30% of work in 12 days. If efficiency of C is 50% more than A, then find in how many days A, B and C together will be completed 90% of work ?
5 days
8 days
12 days
6 days
4 days
Option D
Total days required to complete the work by A = 8/40 * 100 = 20
total days required to complete the work by B = 12/30 * 100 = 40
LCM of 20 and 40 = 40
efficiency of A = 40/20 = 2
efficiency of B = 40/40 = 1
efficiency of C = 2 * 150/100 = 3
days required = 40/6 * 90/100 = 6 days

3. The ratio of present age of A and B is 3 : 4. If the ratio of age of A after 6 years and age of B before 4 years is 6 : 5, then find the age of B after 4 years ?
42 years
25 years
26 years
28 years
40 years
Option D
Let the present age of A and B = 3x and 4x
3x + 6/ 4x – 4 = 6/5
15x + 30 = 24x – 24
x = 6
the age of B after 4 years = 4x + 4 = 28 years

4. A man goes from a place A to B at a speed of 12 km/hr and returns from B to A at a speed of 18 km/hr. What is the average speed for the whole journey ?
12 km/hr
24 km/hr
14 km/hr
14 2/5 km/hr
15 2/5 km/hr
Option D
Average speed = 2xy /x + y
= 2 * 12 * 18/12 + 18 = 14 2/5 km/hr

5. A boat covers 12 km upstream and 18 km downstream in 3 hours while it covers 36 km upstream and 24 downstream in 6 1/2 hours, what is the speed of stream ?
5 km/hr
4 km/hr
6 km/hr
2 km/hr
8 km/hr
Option D
12/x – y + 18/x + y = 3
36/x – y + 24/x + y = 13/2
let x – y = a, x + y = b
12/a + 18/b = 3
36a + 24/b = 13/2
By multiplying ‘3’ in equation (i)
36/a + 54/b = 9
36/a + 24/b = 13/2
30/b = 9 – 13/2
b = 12
36/a + 9/2 = 9
36/a = 9/2
a = 8
x – y = 8
x + y = 12
2x = 20
x = 10
y = 2

6. Directions : What will come in place of questions marks (?) in the following number series ?
345, 358, 375, ?, 417, 446
380
382
392
394
396
Option D
The series is, (+ 13), (+ 17), (+ 19), (+ 23), (+ 29),

7. 5, 11, 35, 143, 719, ?
4240
4319
4465
4978
4565
Option B
The series is, ( * 2 + 1), ( * 3 + 2), ( * 4 + 3), ( * 5 + 4), ( * 6 + 5),

8. 20, 18, 38, 56, 94, ?
155
100
120
125
150
Option E
The series is, (20 + 18), (18 + 56), (56 + 94)

9. 35, 40, 55, 80, 115, ?
145
180
160
172
165
Option C
The series is, (+ 5), (+ 15), (+ 25), (+ 35), (+ 45),

10. 35, 18, 19, 30, ?, 157.5
64
62
58
96
86
Option B
The series is, ( * 5 + .5), (* 1 + 1), (* 1.5 + 1.5), (* 2 + 2), (* 2.5 + 2.5)