Question

solve each problem. show all your work!
15 sarah has 12 marbles, and her friend gives her some more. she now has 23 marbles all together. write an equation that represents m the number of marbles sarah was given and solve for m.
16 kaitlyn buys a pack of socks for $6.79 and now has $3.21 left over. which equation represents the situation if x is the amount kaitlyn had before she bought the socks?
a) 6.79x = 3.21
b) x - 6.79 = 3.21
c) x + 6.79 = 3.21
d) 3.21 - x = 6.79
17 derek gives a cashier a 20 dollar bill to buy a personal pizza. he is given $8.74 as change. which equation represents the situation if c is the cost of the pizza?
a) c + 20 = 8.74
b) 20 - c = 8.74
c) 8.74c = 20
d) 8.74 - c = 20
18 julio has $36 to spend on books this week. after going to the store to buy books she now has three dollars left over. which equation can be used to find b, the amount of money julia spent on books last week?
a) 3b = 36
b) \\(\frac{1}{3}b = 36\\)
c) b + 3 = 36
d) 36 - b = 3

Explanation:

Problem 15

Step1: Define the equation

$12 + m = 23$

Step2: Isolate $m$

$m = 23 - 12$

Step3: Calculate $m$

$m = 11$

Problem 16

Step1: Match scenario to equation

Initial money minus cost equals leftover: $x - 6.79 = 3.21$

Problem 17

Step1: Match scenario to equation

Amount paid minus pizza cost equals change: $20 - c = 8.74$

Problem 18

Step1: Match scenario to equation

Total budget minus spent equals leftover: $36 - b = 3$

Answer:

1. For problem 15: The equation is $12 + m = 23$, and $m=11$
2. For problem 16: B) $x - 6.79 = 3.21$
3. For problem 17: B) $20 - c = 8.74$
4. For problem 18: D) $36 - b = 3$