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Dad is 4 times as old as his son Jim is now. In 10 years, Dad's age will be 20 years more than twice Jim's age. If D = dad's age now and J = Jim's age now, how old is Jim?

User Subchap
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1 Answer

15 votes
15 votes

Answer:

Jim is 5

Explanation:

word problems can be sort of like translation questions

'times' means multiply

'as old as' means equal or =

'will be' means equal or =

'more than' means plus or +

when I saw

"Dad is 4 times as old as his son Jim is now"

I knew needed to make

Jim = x &

Dad = 4x

when I saw

"In 10 years, Dad's age will be 20 years more than twice Jim's age"

I knew

'Dad's age' means 4x

'In 10 years' means 10 +

'will be' means equal sign or =

'20 years more than' means 20 +

'twice Jim's age' means 2x

sentence can be re written

4x+10=20+2x

'if D = dad's age now' means 4x=D (Dad)

'J = Jim's age now' means x = J (Jim)

I solved for x

4x+10=20+2x

2x=10

x=5

then I checked the math

today

x = Jim = J = 5

4x = Dad = D = 20

'in 10 years'

Dad is 20 + 10 = 30

means

does 30 = 20 years more than twice Jim's age?

does 30 = 20 + 2x ?

does 30 = 20 + 2(5)?

does 30 = 20 + 10?

does 30 = 30?

yes!

it checks out!

User MarkoCen
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2.6k points