The average age of three boys is 15 yr. If the ratio of their ages is 3 : 5 : 7, what is the age of the oldest boy?


A) 7 year

B) 14 year

C) 20 year

D) 21 year

Correct Answer:
D) 21 year

Description for Correct answer:
Total age of all the three boys = 3 X 15 = 45 yr.

Ratio of ages = 3 : 5 : 7

Age of the oldest boy

= \( \large\frac{7}{3 + 5 + 7}\times 45 = \frac{7}{15} \times 45 = 21 yr \)

Part of solved Average questions and answers : >> Aptitude >> Average








Comments

No comments available




Similar Questions
1). The average weight of 60 students in a class was calculated to be 40 kg. Later, it was found out that the weight of one of the students was calculated as 36 kg. Whereas his actual weight was 33 kg. What is the actual average weight of the students in the class?
A). 39.90 kg
B). 39.95 kg
C). 39 kg
D). 38 kg
-- View Answer
2). A person bought some oranges worth Rs.36 from each of the five markets at Rs.1, Rs.1.50, Rs. 1.80, Rs.2 and Rs 2.25 per orange respectively. What is the average price of an orange?
A). RS. 1.91
B). RS. 2.00
C). RS. 1.58
D). RS. 1.80
-- View Answer
3). Average of a, b and c is 11; average of c, d and e is 17; average of e and f is 22 and average of e and c is 17 Find out the average of a, b, c, d, e and f
A). \( 15\large\frac{2}{3} \)
B). \(18\large\frac{1}{2} \)
C). \( 21\large\frac{1}{3} \)
D). \(16\large\frac{1}{2} \)
-- View Answer
4). The average of a man and his two twin sons born on the same day is 30 yr. The ratio of the ages of father and one son is 5 : 2, what is the father's age?
A). 50 yr
B). 30 yr
C). 45 yr
D). 20 yr
-- View Answer
5). If the average of the ages of Rakesh and Mohan is 15, average of the ages of Mohan and Ramesh is 12 and the average of the ages of Rakesh and Ramesh is 13, then the age of Mohan, is
A). 16
B). 13
C). 14
D). 12
-- View Answer


6). A cricketer has a certain average for 10 innings. In the eleventh innings, he scored 216 runs, there by increasing his average by 12 runs. Find out his new average.
A). 96
B). 84
C). 97
D). 87
-- View Answer
7). Nine friends have dinner in a hotel. Eight of them spent Rs 12 each on their meals and the ninth spent Rs. 16 more than the average expenditure of all the nine. Find out the total money spent by them.
A). Rs. 126
B). Rs. 135
C). Rs. 111
D). Rs. 141
-- View Answer
8). The average weight of the students in four sections A, B, C and D is 60kg. The average weight of the students in A, B, C and D individually are 45 Kg, 50 Kg, 72 Kg and 80 Kg respectively. If the average weight of the students of section A and B together is 48 Kg and that of B and C together is 60 Kg, what is the ratio of the number of students in sections A and D?
A). 12 : 7
B). 4 : 3
C). 3 : 2
D). 8 : 5
-- View Answer
9). The average age of students of a class is 15.8 yr. The average age of boys in the class is 16.4 yr and that of the girls is 15.4 year. Find out the ratio of the number of boys to the number of girls in the class
A). 3 : 1
B). 5 : 2
C). 2 : 3
D). 3 : 7
-- View Answer
10). In a certain examination, the average marks of an examinee is 64 per paper. If he had obtained 18 more marks for his mathematics paper and 4 more marks for his English paper, his average per paper would have been 66. How many papers were there in the examination?
A). 11
B). 13
C). 9
D). 15
-- View Answer