Ahobby shop has 4 times as many model airplanes as model helicopters. the total number of models is 35. how many model airplanes does the hobby shop have?

Let's call airplanes "a" and helicopters "h".

The total number of models is 35. This means that a+h=35

4 times as many model airplanes as model helicopters. This means a=4h.

we can substitute this into the previous equation:

4h+h=35
5h=35

dividing by 5:

h=7

so he has 7 helicopters and 4*7=28 airplanes

2.4+3.2t. you get the answer by adding the ones with variables and ones without