p = 2d
d = 2n.....n = 1/2d
q = d - 3
since dimes is mentioned in relation to quarters, pennies, and the nickels, u would use d as ur variable
ur expression would be : d + (2d) + (1/2d) + (d - 3) = total amount of coins...then u would solve for d, the number of dimes. And once u know that, u can sub that answer back into ur original equations to find the number of pennies, quarters and nickels