Answer:
16. d = distance
r = rate
t = time.
We know that the rate = 4, and time = 11.
=> d = 4 * 11
=> d = 44
17. We know that distance = 36, and time = 4.
=> 36 * r* 4
=> 36 = 4r
=> 36/4 = 4r/4
=> r = 9
41+0.10x = 31+0.15x
10 +0.10x=0.15x
10=0.05x
x=10/.05
x= 200 text messages
check 200*0.10 = 20 +41 =61
200*0.15 = 30+31 = 61
they equal each other so number of texts is 200
let's set up an equation:
x-4=9
solve normally:
x=13
