4th grade
posted by Lynnese on .
Bobby has only pennies, dimes, and quarters. One half of Bobby's coins are pennies. One fourth of his coins are quarters. Three of his coins are dimes. How many coins does Bobby have?
please help me figure this one out?

Bobby has 12 coins.
he has 3 dimes, 6 pennies, and 3 quarters 
How did you get your answer? Please explain it to me?

i used the equation: 1/2x+1/4x+3=x
then add 1/2x and 1/4x: 3/4x+3=x
then subtract 3/4x on both sides:3=1/4x
then divide by 1/4x: 12=x
12 coins is the answer :) 
1/2 + 1/4 = 3/4
so 3/4 of his coins must be made up of pennies and quarters.
so that means the remaining 1/4 must be dimes
But we know that he has 3 dimes
think this way: 1/4 of what number is 3 ?
or
3 divided by 1/4 is .... ?