Welcome Guest

← Back to Mathematical Skills

Mathematical Skills | Average

Q. No. 25:The average age of all students of class is 24 year. The average age of boys of the class is 29 year and that of girls is 20 year. If the number of girls in the class is 25, then find the number of boys in the class.
A :
30
B :
15
C :
24
D :
20
Q. No. 26:There are 6 boys in the room. The ages(in years) of exactly three boys are prime numbers and ages(in years) of the other three boys are even numbers. If the ages(in years) of all the 6 students in the room are in A.P, then what is the average age(in years) of the boys in the room?
A :
5.5
B :
6
C :
4.5
D :
6.5
Q. No. 27:A firm produces units of tyres (x>0) at a total cost of Rs (100x - 3x2 +x3/3). Then, the average cost per tyre is minimized for x, is equal to
A :
40
B :
60-40√2
C :
60+40√2
D :
45
Q. No. 28:A box contains 85 nuts each of 100g and 94 bolts each of 150g. If the entire box with its contents weighs 42.5 kg, then what is the weight of the empty box ?
A :
22.5 kg
B :
19.9 kg
C :
20.6 kg
D :
18.9 kg
Q. No. 29:In an increasing sequence of 10 consecutive integers, the sum of first 5 integers is 560. What is the sum of the last 5 integers in the sequence ?
A :
585
B :
580
C :
570
D :
595
 29  1 ...345
Average
Easy
Moderate
Difficult