Question

. A sum of Rs 1000 is in the form of denominations of Rs 10 and Rs 20. If the total number of notes is 60, find the number of notes of each type. ​

Answer 1

$let \: the \: number \: of \: notes \: of \: rs.10 = x \\ therefore \: the \: number \: of \: notes \: of \: rs.20 = 60 - x \\ according \: to \: given \: condition \: \\ 10x + 20(60 - x) = 1000 \\ 10x + 1200 - 20x = 1000 \\ - 10x = 1000 - 1200 \\ - 10x = - 200 \\ x = \frac{ - 200}{ - 10} = 20 \\ \\ therefore \: the \: number \: of \: notes \: of \: denomination \: of \: rs.10 = 20 \\ the \: number \: of \: notes \: of \: denomination \: of \: rs.20 = 60 - 20 \\ = rs.40$