In checking the petty cash; a clerk counts q quarters, d dimes, n nickels, and p pennies,

Question:

In checking the petty cash; a clerk counts “q” quarters, “d” dimes, “n” nickels, and “p” pennies, later he discovers that x of the nickels were counted as quarters and x of the dimes were counted as pennies. (Assume that x represents the same number of nickels and dimes.) What must the clerk do to correct the original total?