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16 votes
16 votes
Harpreet, Sukhpreet and Komalpreet are three sisters. Sukhpreet is x years old. Harpreet is 3 years older than Sukhpreet. Komalpreet is twice the age of Harpreet. If the average age of the three sisters is 15, how old is Harpreet?

User Charles Stewart
by
2.7k points

1 Answer

19 votes
19 votes

Answer:

12

Explanation:

Givens

Harpreet = x + 3

Sukhpreet = x

Komalpreet = 2*(x + 3)

Average Age = 15

Equation

[(x + 3) + x + 2*(x + 3) ] / 3 = 15 Multiply both sides by 3

Solution

3 [(x + 3) + x + 2*(x + 3) ] / 3 = 15 * 3 Combine

[(x + 3) + x + 2*(x + 3) ] = 45 Remove the brackets

x + 3 + x + 2x + 6 = 45 Combine like terms

4x + 9 = 45 Subtract 9 from both sides

4x + 9 - 9 = 45 - 9 Combine

4x = 36 Divide by 4

4x/4 = 36/4

x = 9

Answer

Harpreet is x+ 3 = 9 + 3 = 12

User Zruty
by
3.2k points
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