D is partly constant and partly varies with v.when v=40,D=150 and when v=54,D=192

I) find the formula connecting D and V
ii) find D when V=73

3 answers

I) D = (192-150)/(54-40) * (V-40) + 150

ii) D = (192-150)/(54-40) * (73-40) + 150
= 202
I have no idea what the bot is doing here, anyway ....

"D is partly constant and partly varies with v"
---> D = mv + c
when v=40,D=150 ---- 150 = 40m + c
when v=54,D=192 --- 192 = 54m + c
subtract them:
14m = 42
m = 3, then in 150 = 40m + c
150 = 120 + c
c = 30

so D = 3v + 30
and when v = 73, D = 3(73) + 30 = 249
Whew, thanks Tammy. Answered is driving me crazy