At the city museum, child admission is $6.40 and adult admission is $9.60. On Tuesday, 160 tickets were sold for a total sales of $1305.60. How many adult tickets were sold that day?

numbers of adult tickets

X = children

Y = adult

6.40x + 9.60y = 1305.60

x + y = 160

x=160-y

6.40 (160-y) + 9.60y = 1305.60

1024 + 6.40y + 9.60y = 1305.60

1024 = 3.2y = 1305.60

3.2y = 281.6

Y = 281.6/3.2 = 88

So 88 adult tickets were sold

Double check now

X = 160-y

X=160-88 = 72

6.40 x 72 = 460.80

9.60 x 88 = 844.80

844.80 + 460.80 = 1305.60 this checks

88 + 72 = 160 this checks