After 16 years

After 16 years, Dana will be five times older than she was four years ago. After how many years will Dana celebrate her 16th birthday?

Correct answer:

x =  7

Step-by-step explanation:


r+16 =5(r-4)
x = 16-r

r+16 =5·(r-4)
x = 16-r

4r = 36
r+x = 16

Row 2 - 1/4 · Row 1 → Row 2
4r = 36
x = 7


x = 7/1 = 7
r = 36/4 = 9

r = 9
x = 7

Our linear equations calculator calculates it.



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