IBPS RRB PO 2020 – Daily Math Quiz Day – 2
IBPS RRB PO 2020 – Daily Math Quiz Day – 2
1.(√5 – √10)2 + (√2 + 5)2 = x3 – 22
What value should come in place of the x in the following questions?
A) 3
B) 5
C) 8
D) 7
E) 4
- Answer
Option E
Solution:
(√5 – √10)2 = √52 + √102 – 2*√5*√10 = 5 +
10 – 2*√5*√2*√5 = 15 – 10√2
(√2 + 5)2 = 2 + 25 + 10√2
So 15 – 10√2 + 27 + 10√2 = x3 – 22
15+27+22 = x3
2. 2x2 – 17x + 36 = 0,
3y2 – 28y + 64 = 0
A) If x > y
B) If x < y
C) If x ≥ y
D) If x ≤ y
E) If x = y or relation cannot be established
2. Answer
Option E
Solution:
x = 4, 9/2
y = 4, 16/3
Put all values on number line and analyze
the relationship
4…….9/2…….. 16/3
3. In a school the number of boys and girls are in the ratio of 4:7. If the number of boys are increased by 25% and the number of girls are increased by 15%. What will be the new ratio of number of boys to that of girls?
a) 100:131
b) 100:151
c) 100:161
d) 100:181
e) None of these
3. Answer & Explanation
Answer – c) 100:161
Explanation :
Boys = 4x and girls = 7x
Ratio = 4x*125/100 : 7x*115/100 = 100:161
4. 5, 6, 14, 45, 184, ?
1.927
2.932
3.925
4.918
5.920
4. Answer – 3 – 925
Explanation :
5 * 1 + 1 = 6
6 * 2 + 2 = 14
14 * 3 + 3 = 45
45 * 4 + 4 = 184
184 * 5 + 5 = 925
5. 50 51 47 56 42 65 29
Find out the wrong number
1. 51
2. 47
3. 56
4. 42
5. 65
The series is 50 + 1^2 = 51, 51 – 2^2 = 47, 47 + 3^2 = 56, 56 – 4^2 = 40, 40 + 5^2 = 65, 65 –
6^2 = 29.
Hence, there should be 40 in place of 42
6. An article is sold at 33(1/3)% profit. If it had been sold at a profit of 40%,it would
have fetched Rs50 more. Find cost price of article?
A) 700
B) 750
C) 600
D) 650
E) 720
6. View Answer
Option B
Solution:
1st 33(1/3)% profit so CP = 3, and SP =
3+1 = 4
2nd 40% = 2/5. So CP = 5, SP = 7
Now CP is same so make CP same
CP…….. SP
15………..20
15………….21
20 to 21 is + 1, so 1= 50 [increase in SP]
So 15=750
7. If the simple interest on a certain sum of money is 4/25 of the sum and the rate per
cent equals the number years, then the rate of interest per annum is:
A) 4%
B) 5%
C) 8%
D) 10%
E) None
7. Answer
Option A
Solution:
Let the principal be Rs x.
Then the SI =4/25x
Rate of interest = Time
r= (100*4/25x)/ x*r
r2 =400/25
r=20/5=4%
8. Three taps P, Q and R can fill a tank in 12, 15 and 20 hours respectively. If P is open all
the time and Q, R are open for one hour each alternatively, the tank will be full in
1.3 hours
2. 2 hours
3. 7 hours
4. 4 hours
5. None of the Above
- Answer & Explanation
Answer – C. 7 hours
Explanation :
(P + Q)’s 1 hour work = 1/12 + 1/15 = 3/20
(P + R)’s 1 hour work = 1/12 + 1/20 = 2/15
For 2 hrs = (3/20 + 2/15) = 17/60
For 6 hrs = (3*17/60) = 17/20
Remaining Part = 1 – 17/20 = 3/20 filled by P
and Q in 1 hour
9. A bus covers a total distance in 12hours. It covers first half at 10km/hr and 2nd half at 14km/hr. find the distance covered by bus?
A) 140km
B) 120km
C) 160km
D) 145km
- View Answer
Option A
Solution:
This is concept of average speed.
So
Distance = average speed * time
= 2*10*14/(10+14) *12 = 140km
10. In how many ways a group of 4 men and 3 women be made out of a total of 8 men and 5
women?
A) 720
B) 140
C) 120
D) 360
E) 210
Answer & Explanation
B) 140
Explanation:
Total ways = 8C4*5C3