Explanation:
25 cents = $0.25
the ratio is 5/0.25 (5 dates for $0.25)
now we need to convert this to $5 in the denominator. and we need to multiply the numerator with the same factor.
and then the numerator will tell us how many dates we get for $5 in the denominator.
0.25 × x = 5
x = 5/0.25 = 20
indeed, 20 quarters = $5
so, we do
5/0.25 × 20/20 = 100/5
that means we can buy 100 dates for $5.