You can
put this solution on YOUR website!working in cents
let n=number of coins
"The average value of all the pennies, nickels, dimes and quarters in Bob's pocket is 20 cents" __ 20n
"If he had one more quarter, the average would be 21 cents" __ 20n+25=21(n+1)
20n+25=21n+21 __ 4=n
4 coins worth 80 cents means 3 quarters and a nickel
__ no pennies or dimes
