Question: 21 -
Find the smallest number of 4 digits which is exactly divisible by 12, 15, 21 and 30.
-
1420
-
1260
-
1580
-
1056
Answer:
1260
Solution:
Least 4 digit number = 1000
LCM of (12, 15, 21, 30) = 420
On dividing 420 by 1000, leaves remainder = 160
So answer = 1000 + (420 – 160)
Least 4 digit number = 1000
LCM of (12, 15, 21, 30) = 420
On dividing 420 by 1000, leaves remainder = 160
So answer = 1000 + (420 – 160)
Question: 22 -
Find the least number which when divided by15, 21, 24 and 32 leaves the same remainder 2 in each case.
-
3456
-
3266
-
3362
-
3360
Answer:
3362
Solution:
It will be the LCM of these numbers + 2
So 3360 + 2
It will be the LCM of these numbers + 2
So 3360 + 2
Question: 23 -
The sum of three consecutive even numbers is 42. Find the middle number of the three?
-
18
-
16
-
14
-
24
Answer:
14
Solution:
Three consecutive even numbers (2P - 2), 2P, (2P + 2).
(2P - 2) + 2P + (2P + 2) = 42
6P = 42 => P = 7.
The middle number is: 2P = 14.
Three consecutive even numbers (2P - 2), 2P, (2P + 2).
(2P - 2) + 2P + (2P + 2) = 42
6P = 42 => P = 7.
The middle number is: 2P = 14.
Question: 24 -
What least number must be subtracted from 13601, so that the remainder is divisible by 87 ?
-
23
-
37
-
29
-
31
Answer:
29
Solution:
87)13601(156
87
-----
490
435
-----
551
522
-----
29
-----
Required number is 29.
87)13601(156
87
-----
490
435
-----
551
522
-----
29
-----
Required number is 29.
Question: 25 -
Two containers contain 50 and 125 litres of water respectively. Find the maximum capacity of a container which can measure the water in each container an exact number of times(in litres)
-
11
-
25
-
15
-
12
Answer:
25
Solution:
HCF of 50 and 125 = 25
HCF of 50 and 125 = 25