In customary units, the length of a car would be in feet.
For the first one, subtracting the membership fee, we have 9 dollars to buy as many 1.50 dollar videos as possible. 9/1.50 works well as 6, so he can buy 6.
Subtract 160 from 480 to get 320, and divide that by 80 to get 4 days
We can do some guess and check here. If he buys 2 t shirts, that's 12*2=24 and 41-24=17. 17 is not a factor of 5, so that doesn't work. If he buys 3, that's 12*3=36 and 41-36=5. 5 is a factor of 5, so that works!
For this, we need to find the lowest common multiple of 12 and 15....
common multiples of 12 : 12,24,36,48,60
common multiples of 15 : 15,30,45,60
LCM = 60
the caller that will be the first to win both is the 60th caller
The perimeter is just adding all the sides together.
a.) 180 = 40 + 40 + x + x
180 = 80 + 2x Subtract 80 on both sides
100 = 2x Take 1/2 of 100 to get x
x= 50cm
b.) 1000 = 150 + 150 + x + x
1000 = 300 + 2x Subtract 300 on both sides
700 = 2x Take 1/2 of 700 to get x
x = 350