Question
Average of first 3 numbers is half the average of next 6
numbers. If the average of all 9 numbers is 15, find the sum of the last 6 numbers.Solution
Let the sum of the last 6 numbers be 'n'.
(sum of first 3 numbers) ÷ 3 = 0.5 × (n/6)
⇒ Sum of first 3 numbers = 0.25n
Total sum = n + 0.25n = 1.25n
Average of 9 numbers = 1.25n ÷ 9 = 15
⇒ 1.25n = 135
⇒ n = 108
Find the value of 24 -Â 3Â
The ratio of the incomes of Vineet and Vidya is 5:2 respectively. Vineet saves 30% of his income while Vidya saves 20% of his income. The sum of their e...
The simple interest on a sum of money for 3 years is 1,200 at a rate of 10% per annum. What is the compound interest on the same sum for the same time a...
A principal of ₹5000 is invested at a simple interest rate of 8% per annum. What will be the interest earned after 3 years?
The average of a, b and c is 8 less than d. If the average of a, b, c and d is 42, and the average of b and c is 43. then find the average of (a-6) and ...
Find the distance between points A(2, 3) and B(7, 8).
A milkman has a 60-liter mixture of milk and water in the ratio of 7:5. He sells 'x' liters of the mixture and replaces it with the same amount of a new...
The compound interest earned on an investment of Rs. 'Y' over 2 years at an annual compound interest rate of 12%, compounded yearly, amounts to Rs. 1,27...
A person 'P' contributes 25% of their monthly income to two NGOs, 'X' and 'Y', in the ratio of 12:15. If the donation amount given to NGO 'Y' exceeds th...
Relevant for Exams:
