SOLUTION: A can EAT pizza in 10 min B can eat pizza in 15 min Their grandfather can eat a pizza in 30 min If, A, B & their grandfather all start eating the same pizza at the same time,

Algebra ->  Average -> SOLUTION: A can EAT pizza in 10 min B can eat pizza in 15 min Their grandfather can eat a pizza in 30 min If, A, B & their grandfather all start eating the same pizza at the same time,       Log On


   

Question 885963: A can EAT pizza in 10 min
B can eat pizza in 15 min
Their grandfather can eat a pizza in 30 min
If, A, B & their grandfather all start eating the same pizza at the same time, how many seconds does it take them to finish the pizza?
240 sec
360 sec
300 sec
330 sec
Answer by basketball1127(19) About Me  (Show Source):
You can put this solution on YOUR website!
Let x= 1 whole pizza
A can eat x/10 of the pizza in 1 min
B can eat x/15 of the pizza in 1 min
Their grandfather can eat x/30 of the pizza in 1 min
x%2F10%2Bx%2F15%2Bx%2F30=1+min
%283x%2B2x%2B1x%29%2F30=1+min
6x%2F30=1+min
x%2F5=1+min
x=5+mins
x=300 seconds