Question

2 part time jobs. First job is $8hr at library. second job is $15hr for construction. Works 25 hrs per week. Enjoy's working at library more. How many hours can he work at library at earn at least $300 week?

Answer 1

Let L be the number of hours working at the library and C the number in construction.

First note that L + C = 25, so C = 25 - L

Now the total amount earned is

8L + 25C = 8L + 25(25 - L) = 575 - 17L

and we want that that amount to be at least 300

So 575 - 17L >= 300
275 >= 17 L
17L =< 275
L =< 4.41

So he should work at the library no more than ~4.4 hours.

Answer 2

do you factor the rate the student makes in construction @$15?

Answer 3

Oh whoops, I thought it was $25. Well, same calculation, slightly different answer.

Answer 4

If you use $15 for Construction job, you end up with
7L < 75
So L < 10.7.

Hence no more than 10.7 jobs. Sorry about that.

Answer 5

cheers. :)