When Lauren cashed a check for $210, the bank teller gave her 14 bills, some were $20 bills and the rest were $10 bills. How many of each bill did Lauren get?

Question

Using Elimination or Substitution

Answer 1

Hello, Nene,

We have two unknowns, so we need at least two equations to solve.

Let X = Number of $10 bills, and

Y = Number of $20 bills.

We know that: X + Y = 14 bills

We also know that: 10X + 20Y = 210 (the total of X $10 bills and Y $20 bills).

Let's rearrange the first equation: X = 14 - Y, and substitute it in the second:

10*(14-Y) + 20Y = 210

Solve for Y

280-20Y+10Y = 210

-10Y = -70

Y = 7

Since Y = 7, X is (14-7) or 7, also.

Check the values:

7*20 = 140

7*10= 70

Total = 210

I hope this helps, Bob