The points P, Q, R and S all lie on the same line segment, in that order, such that the ratio of PQ : QR: RS is equal to 1:4:1. If PS = 18, find QR.

Hassan bought a package of tofu. the temperature of the tofu was 14° celsius when hassan put the package into the freezer. he left the tofu in the freezer until it reached –19° celsius. which expressions explain how to find the change in temperature, in degrees celsius, of the package of tofu? select three that apply.