Question
The average of a set of 's' numbers is 30. If 50 is
added to the set, then the average of the set becomes 30.2. Find the value of '4 X (s - 5)'.Solution
Sum of all 's' numbers = 30s
ATQ:
(30s + 50) / (s + 1) = 30.2
Multiplying both sides by (s + 1):
30s + 50 = 30.2(s + 1)
30s + 50 = 30.2s + 30.2
50 - 30.2 = 30.2s - 30s
19.8 = 0.2s
s = 99
4 X (s - 5):
4 X (99 - 5) = 4 X 94 = 376
Present ages of P and Q are in the ratio 5:8 respectively. If Q’s age, 14 years hence from now will be 4 times of P’s age, 4 years ago from now, the...
A person’s present age is 4/5th of the age of his brother. After 10 years, he will be 9/10th of the age of his brother. How old is the brother at pr...
Six years ago, the age of 'R' compared to the age of 'M' six years from now was in the ratio 4:7. If the current average age of 'R' and 'M' is 33 years,...
- The father is 5 years older than the mother and five times as old as the son. If their current age sum is 110 years, after how many years will the father b...
The ratio of age of A and his son is 9:3. If the difference of their ages 6 years ago is 36, then find the sum of the ages of A and his son together 4 y...
Ratio of present ages of ‘M’ and ‘N’ is 4:3 respectively. After 6 years, ratio of ages of ‘N’ and ‘M’ becomes 5:7 respectively. Find the...
The ratio of the present ages of Aman and Deepak is 3:5. After 5 years, the ratio of their ages will be 5:8. Find the present age of Rohit, who is 7 yea...
7 years ago from now, the ratio of ages of two siblings was 9:8, respectively. 5 years hence from now, the ratio of ages of the younger sibling and the ...
After 8 years, the age of Neha will be 6 years less than 2 times of her age, 5 years back. What is Neha’s present age?
M and S currently have ages in the ratio of 3:4. R's present age is 50% more than S's present age. The ratio of M's age one year from now to R's age thr...
Relevant for Exams:
