As a lifeguard, Sara earns a base pay of $80 per day. If her day involves swim instruction, Sara earns an additional $9 per hour, where t represents the number of hours she gives instruction. Part A: Write an expression to represent how much money Sara earns in a day

Part B: Evaluate your expression to determine how much money Sara earns if she does 7 hours of swim instruction

Part A:   y = 9t + 80

Part B:   $143

Step-by-step explanation:

When solving this question all we need to keep in mind is the fact that if Sarah will not give swim instructions she will get $80 dollars just because she was there as a lifeguard. Then lets think about what will happen when she will work "t" hours? Well, she will get $80 for just being there as a life guard and then on top of that she will get $9t (because she gets $9 every hour she gives instructions). So just now we made an equation that we can use to express how much money Sara earns a day. It can be written mathematically as the following

Let "y" be the among of money Sara will get paid at the end of the day. then...

y = 9t + 80

In order to answer Part B of this question we will just have to plug 7 instead of "t" into he expression that we made in part A. And so we get

y = 9t + 80

y = (9)(7) + 80

y = 63 + 80

y = 143

the least common denominator is 40

$15 each

step-by-step explanation:

$45/3 children= $15 each