Mathematics, 23.07.2019 11:00 skgoldsmith

There is a happy family consisting of 2 parents and kids. the average age of the family is 20. but if we exclude one parent whose age is 40, the average age of the family drops to 15. find the number of kids in the family.

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Let k be the number of kids. Size of family = 2 + k.
Total of all the ages = 20(2 + k).
Total of all the ages excluding 40 year old parent = 20(2 + k) - 40 = 20k.
15 = 20k/(1 + k)
15 + 15k = 20k.
k = 3

Answer from: pattydixon6

Suppose there are n people in this family
one parent is age 40, suppose the rest of the family add up to be y years old
the average is (40+y)/n=20 =>40+y=20n
exclude the 40-year-old parent, the sum of age is still y, the number of family is (n-1), the average is y/(n-1)=15 =>y=15n-15
substitute y=15n-15 in the first equation: 40+(15n-15)=20n
solve for n: 5n=25, n=5
there are a total of 5 people in this family, there are 3 kids.

Answer from: Quest

step-by-step explanation:

step 1 distribute 2 to every term in the parentheses

step 2 add 10 on both sides of the equal sign

Answer from: Quest

the most boring ever written

step-by-step explanation:

i am writing something. yes, i plan to make it the most boring thing ever written. i go to the store. a car is parked. many cars are parked or moving. some are blue. some are tan. they have windows. in the store, there are items for sale. these include such things as soap, detergent, magazines, and lettuce. you can enhance your life with these products. soap can be used for bathing, be it in a bathtub or in a shower. apply the soap to your body and rinse. detergent is used to wash clothes. place your dirty clothes into a washing machine and add some detergent as directed on the box. select the appropriate settings on your washing machine and you should be ready to begin. magazines are stapled reading material made with glossy paper, and they cover a wide variety of topics, ranging from news and politics to business and stock market information. some magazines are concerned with more recreational topics, like sports card collecting or different kinds of hairstyles. lettuce is a vegetable.

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