# Numerical Ability Practice Questions for IBPS RRB (Set – 5)

Numerical Ability Practice Questions for IBPS RRB (Set – 5)
1. In what time will a railway train 60 m long moving at the rate of 36 kmph pass a telegraph post on its way?
a) 9 sec
b) 8 sec
c) 7 sec
d) 6 sec
e) 5 sec
2. A and B complete a work in 6 days. A alone can do it in 10 days. If both together can do the work in how many days?
a) 3.75 days
b) 4 days
c) 5 days
d) 6 days
e) 7 days
3. The proportion of copper and zinc in the brass is 13:7. How much zinc will there be in 100 kg of brass?
a) 20kg
b) 35kg
c) 55kg
d) 14kg
e) 42kg
4. A boat goes 100 km downstream in 10 hours, and 75 m upstream in 15 hours. The speed of the stream is?
a) 7kmph
b) 5kmph
c) 3kmph
d) 2.5kmph
e) 6kmph
5. The average of 11 numbers is 10.9. If the average of first six is 10.5 and that of the last six is 11.4 the sixth number is?
a) 11.0
b) 11.2
c) 11.3
d) 11.4
e) 11.5
Directions (6 – 10): In each of these questions, two equations (I) and (II) are given. Solve both the equations and give answer
a) if x > y
b) if x < y
c) if x ≥ y
d) if x ≤ y
e) if x = y or no relation can be established between ‘x’ and ‘y’.
6. I. 63x -194 √x +143 = 0; II. 99y - 255 √y +150 = 0
7. I. x - 7 √(3x) + 36 = 0; II. y -12 √(2y) + 70 = 0
8. I. x^2 - 7 √7x + 84 = 0; II. y^2 - 5 √5y + 30 = 0
9. I. 16x^2 – 40x – 39 = 0; II. 12y^2 – 113y + 255 = 0
10. I. 6x^2 + 13x = 12 – x; II. 1 + 2y^2 = 2y + 5y/6
Solutions:
1. D) T = 60/36 * 18/5 = 6 sec
2. A) 1/6 + 1/10 = 8/30 = 4/15
15/4 = 3.75 days
3. B) 7/20 * 100 = 35
4. D) 100 --- 10             DS = 10
? ----  1
75 ---- 15         US = 5
? ----- 1           S = (10 - 5)/2
= 2 2 ½ kmph
5. D) 1 to 11 = 11 * 10.9 = 119.9
1 to 6 = 6 * 10.5 = 63
6 to 11 = 6 * 11.4 = 68.4
63 + 68.4 = 131.4 – 119.9 = 11.5
6th number = 11.5
6. E) ReI. 63x -194 √x +143 = 0
or 63x -117 √x - 77 √x +143 = 0
or (7 √x -13)(9 √x -11) = 0
x = 169/49, 121/81
II. 99y - 255 √y +150 = 0
or 99y - 90 √y -165 √y +150 = 0
or (11 √y -10)(9 √y -15) = 0
y = 100/121, 225/81
Therefore relation cannot be established between x and y.
7. B) I. x - 7 √(3x) + 36 = 0
or x - 7 √3. √x + 36 = 0
or x - 3 √3 √x - 4 √3 √x + 36 = 0
or ( √x - 3 √3)(√ x - 4 √3) = 0
x = 27, 48
II. y - 5 √(2y) - 7 √(2y) + 70 = 0
or y - 5 √2 √y - 7 √2 √y + 70 = 0
or ( y - 5 √2)( y - 7 √2) = 0
y = 50, 98
x < y
8. A) I. x^2 - 7 √7x + 84 = 0
or (x - 4 √7)(x - 3 √7) = 0
x = 4 √7, 3 √7
II. y^2 - 5 √5y + 30 = 0
or (y - 2 √5)(y - 3 √5) = 0
y = 2 √5, 3 √5
x > y
9. B) I. 16x^2 - 40x - 39 = 0
or 16x^2 - 52x + 12x - 39 = 0
or (4x- 13) (4x + 3)
x = 13/4, -3/4
II. 12y^2 - 113y + 255 = 0
or 12y^2 - 45y - 68y + 255 = 0
or (4y - 15) (3y - 17) = 0
y = 15/4, 17/3
Therefore y > x or, x < y
10. D) I. 6x^2 + 14x = 12
3x^2 + 7x – 6 = 0
(x + 3) (3x – 2) = 0
x = – 3, 2/3
II. 1 + 2y^2 = 17y / 6
12y^2 – 17y + 6 = 0
12y^2 – 8y – 9y + 6 = 0
4y (3y – 2) – 3 (3y – 2) = 0
(3y – 2) (4y – 3) = 0
y = 2/3, 3/4
Hence, y ≥ x