If sandy can decorate a cake in 3 hr and eric can decorate the same cake in 5 hr what is their hourly rate working together

we are given

sandy can decorate a cake in 3 hr

so,

In 1 hour , sandy can decorate

part of cake

Eric can decorate the same cake in 5 hr

so,

In 1 hour , sandy can decorate

part of cake

so, when they work together

In 1 hour , Sandy and Eric decorate

so, their hourly rate is

.............Answer

the answer is 1/4

step-by-step explanation:

i'm assuming that it's c.)   volcanoes built the mountains and earthquakes tore them down.