:morris gave his mother his savings of 105 bills, consisting of twenty-dollar and ten-dollar bills. after she counted the money, his mother told morris that he had $1,550. how
many ten-dollar bills did morris have?

ten-dollar bills = 55 pieces

Step-by-step explanation:

Given:

Total number of bills = 105

Total value = $1550

Assume:

twenty-dollar bills = x

ten-dollar bills = 105 - x

Solve:

20x + 10(105 - x) = 1550

20x + 1050 - 10x = 1550

10x + 1050 = 1550

10x = 500

x = 50

twenty-dollar bills = x = 50

ten-dollar bills = 105 - x = 105 - 50 = 55

Check:

twenty-dollar bills =50 x 20 = $1000

ten-dollar bills = 55 x 10 = $550

Total = $1000 + $550 = $1550

c.

step-by-step explanation:

because first you have to add the 4x, 9x, and the 7x together and you get 20x and then you add the last numbers up and you get 5and then you put the subtraction sign in there and that's how you get the answer.