Lisa needs 125 pieces of candy for her guests at a party she is hosting. The candies come in packages of 35. She already has 20 pieces of candy left over from a previous party. How many packages of candy will Lisa have to buy to have 125 pieces of candy exactly? Create a two-step equation that models this problem and select which of the values below satisfies that equation.
A.
2
B.
3
C.
4
D.
5

Question

Lisa needs 125 pieces of candy for her guests at a party she is hosting. The candies come in packages of 35. She already has 20 pieces of candy left over from a previous party. How many packages of candy will Lisa have to buy to have 125 pieces of candy exactly? Create a two-step equation that models this problem and select which of the values below satisfies that equation.
A.
2
B.
3
C.
4
D.
5

anonymous · Answer

$$B=(125-20)/35$$  Where B is the number of Bags.  The first part of the equation, 125-20, accounts for the total number of pieces of candy needed, minus the number that Lisa already has.  When solving this step, we see that Lisa needs 105 more pieces. Since they're sold in bags of 35, we divide the number of pieces she needs (105), by the number in each bag (35) to determine how many bags she needs:  105/35=3

anonymous · Answer

so basically you subtract how many she had left over with what she started with?

anonymous · Answer

Right, the question said she needs to have exactly 125 pieces, so since she already has 20, we just need to see how many more she needs. Subtracting the amount she already has from the amount she wants to have will show us how many more she needs.  Since we want to have EXACTLY 125 pieces, no more no less, and they are sold in bags of 35, you we have to divide the number of candies we need by the number in each bag. Hopefully it will come out to a whole number so we won't go over or under 125. Fortunately, it came out to be exactly 3 bags of candy.

anonymous · Answer

okay thanks for breaking it down for me :)

anonymous · Answer

i understand it now