Andy is one-fourth as old as his grandfather, who is 76 years old. Write an equation to determine whether Andy is 19 or 22 years old.

We know that if we multiply Andy's age by four we obtain 76. Lets assume that Andy's age its x. so

4*x=76

Now we have to solve equation

4*x=76 / : 4 divide both sides by 4

x=19 - its the answer

A=Andy

G=Andy's Grandfather

A*4=G

G=76

A*4=76

/4

a=19