Question

mr jacob is 55 years old and tony is 7 years old. in how many yearswill mr jacob be 4 times as old as tony

Answer 1

Let Jacobs age be 'J' years when Tony's age is as 4 times as Jacobs. Let Tony's age be 'T'. 

J = 4T 

The difference between Jacobs and Tonys ages doesn't change. (55 -7= 48) 

J - T = 48 

J = 48 + T 

J = 4T 

48 + T = 4T 

48 = 3T 

48/3 = T 

T = 16 

Now Tony is 7. In 9 years

Mr Jacob is 55 years old and tony is 7 years old. in how many years will Mr Jacob be 4 times as old as Tony

Let time it'll take for Mr. Jacob to quadruple Tony's age, be Y

Then: 55 + Y = 4(7 + Y)

55 + Y = 28 + 4Y
Y - 4Y = 28 - 55
- 3Y = - 27
Y, or number of years =
-27/(-3) , or 9