Question

the averge of 3 sisters is 15, 2 sister age is 12 and 15 year.what is age is third sister?​

Answer 1

Answer:

15 this is the answer please give me a five points please please please

Answer 2

Answer:

The age of 3rd Sister = 18

Step-by-step explanation:

Given :

• Average age of 3 sisters = 15

• The age Of 2 sisters = 12 and 15

To find :

• 3rd sister's age = ?

To find Average :

Average = $\sf \: \frac{total \: sum \: of \: ages}{no.of \: ages}$

Solution :

Let, 3rd sister's age be x,

$\sf \to avg \: = \frac{12 + 15 + x}{3} \\ \\ \to \sf \: avg = \frac{27 + x}{3} = 15 \\ \\ \to \sf avg = \: 27 + x = 15 \times 3 \\ \\ \to \sf \: avg \: = 27 + x = 45 \\ \\ \sf\to \: x = 45 - 27 \\ \\ {\frak {\to x = 18}}$

∴ 3rd Sister's age = 18

Let's Verify :

$\sf \: avg \: = \frac{12 + 15 +18 }{3} = 15 \\ \\ \sf \: avg = \frac{45}{3} = 15 \\ \\ \sf \: avg = 15 = 15$

∴ LHS = RHS

Hence Solved !!

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