Peter has 288 coins. 25% of these coins are 1 dollar coins. He wants to increase the number of 1-dollar coins to 64%. How many more 1-dollar coins must he collect?
288 * 0.25 = 72 ($1 coins)
288 - 72 = 216 (non 1-dollar coins)
216 / 36% = x / 64% x = 384
384 - 72 = 312
Peter must collect 312 1-dollar coins.
