Question

The average age of 4 sisters is 20. If the ages of 3 sisters are 16 yr, 18 yr and 20 yr, the age of the fourth sister is . ​

Answer 1

Answer:

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Step-by-step explanation:

Let the ages of sisters be x,y,z

Given that

⇒

3

x+y+z

=15

⇒x+y+z=45

Given that x,y=12,15

⇒12+15+z=45

⇒z=18

Therefore, age of third sister is 18years

Answer 2

Step-by-step explanation:

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