২২২০১
The average of 10 numbers is 7. What will be the new av average if each of the numbers is multiplied by 8?
উত্তর
56
সমাধান
If the numbers are multiplied by 8 then their average will also get multiplied by 8. So, the new average will be 7 x 8 = 56.
২২২০২
A train runs at 45 km per hour. How far does it go in 6 seconds?
উত্তর
75m
সমাধান
we know
distance = speed ×time
so,distance = 45*6*1000/60*60 m = 75 m.
ans:75 metres
২২২০৩
A machine part is packed in a box of size 5cm x 4cm x 2cm. The number of parts that can be packed in a carton of size 25cm x 16cm x 8cm is-
উত্তর
80
সমাধান
Number of parts can be packed = volume of carton / volume of machine part box
= (25 x 16 x 8) / (5 x 4 x 2) = 80
২২২০৪
A's income is 50% less than B's. By how much percent, B's income is more than A's?
উত্তর
100%
সমাধান
Let's B's income = 100
A's income = 50.
Required % =
(100 - 50)/50 × 100 = 100%
ans:100%
২২২০৫
After scoring 85 runs in the 17th innings, a batsman's average run increases by 3. What was his average before the 17th?
উত্তর
34 runs
সমাধান
Let the initial average be A.
ATQ, 16 x A + 85 = 17 x (A + 3)
or, 16A + 85 = 17A + 51
or, 17A - 16A = 85 - 51
or, A = 34 runs
২২২০৬
A train running at the speed of 25 m/s takes 10 seconds to pass a man running at the speed of 10 m/s in the opposite direction. Find the length of the train.
উত্তর
350 meters
সমাধান
Relative speed of the train = 25 + 10 = 35 m/s
So, the length of the train = 35 x 10 = 350 meter.
২২২০৭
Students of a class stand in a queue. If Rajib is 19th in order from both ends, how many students are there in the queue?
উত্তর
37
সমাধান
Number of students in the queue = 19 + 19 - 1 = 37 [1 is sutracted so that he is not counted twice]
২২২০৮
A 6 meter long pole casts 15 meter long shadow. Find the length of second pole if its shadow is 25 meter.
উত্তর
10 meter
সমাধান
shadow is 15 meter long when pole is 6m
shadow is 1 meter long when pole 6/15 m
shadow is 25 meter long = 6/15 *25 m
= 10 m
ans: 10 m
২২২০৯
In a certain country, a person born in every 7seconds and a person dies every 13 seconds. Therefore the birth and death rates account for a population growth rate of one person?
উত্তর
15.17seconds
সমাধান
A person is born every 7 seconds
per second 1/7 person is born
A person dies every 13 seconds
So, per second 1/13 persondies
Population growth rate is
1/7 - 1/13 = 6/91
and rate will be = 91/6 = 15.17 seconds
ans: 15.17 seconds
২২২১০
If X, Y and Z are chosen from the three numbers 2, -3 and 1/2, then what is the largest possible value of the expression (X/Y) *Z2?
উত্তর
36
সমাধান
Let, X=2,Y=½,Z=-3NOW, (X/Y)*Z2=2/½, *(-3)2=36