Carmelo read 38 pages of a book on Monday. He read 2/5 of the remainder on Tuesday. If he still had 72 pages left to read after Tuesday, how many total pages are in carmelo's book

38 + 2 * (x-38) / 5 + 72 = x

you put x-38 because that is the value of reminder he read on tuesday

110 + 2 (x-38) / 5 = x

multiply by 5

550 = 5x-2 (x-38)

550=5x - 2x + 76

474=3x

devide by 3

x=158

that is the number of pages