Word Problem x1

Question

The sum of the ages of Tony and Kristen is 118 years. 9 years ago, Tony's age was 4 times Kristen's age. How old is Tony now?

Answer 1

T+K = 118

T-9 = 4(K-9) = 4K-36

T = 4K-27

T = -K+118

0 = 5K- 145

K = 145/5 = 29

T =118-29 = 89 years old now for Tony

K= 29 years old now

9 years ago K=20 and T =80

80 = 4(20)

Answer 2

The sum of the ages of Tony and Kristen is 118 years. 9 years ago, Tony's age was 4 times Kristen's age. How old is Tony now?

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Let T = Tony's Age

Let K = Kristen's Age

Sum means you are adding...so.....

T + K = 118

T-9 = 4(K-9)..................you must subtract 9 years from both of their ages...Right?

We now have the popular system of 2 equations and 2 unknowns...

T = 118 - K or

T = 4(K-9) + 9 = 4k - 36 + 9 = 4K - 27

Substitute 2nd equation into the first we have.....

4K - 27 + K = 118

with a single variable solve for K

5K -27 = 118

5K = 118 + 27=145......ADD 27 to both sides of the equation

K = 145/5 = 29......so.......T = 118 - 29 = 89...........check........89 + 29 = 118....checks...

9 years ago...89 - 9 = 4 (29-9)....80 = 80......that checks......T = 89 and K = 29

Tony is 89 now.....Right?