5. There are two alloys. The first alloy contains $p \%$ impurities, and the second - respectively $q \%$ impurities. Determine the proportion in which these alloys should be combined to obtain a new alloy containing $r \%$ impurities. In your answer, indicate the ratio of the mass of the first alloy to the mass of the second in the form of a decimal, rounding it if necessary to two decimal places.

$p=70, q=5, r=40$.