Answer:
a) 20x + x = 945
b) Delia has 45 $20 bills and 9 $5 bills.
Explanation:
a)
Let x = number of $20 bills.
"she finds she has 5 times as many 20 dollar bills as 5 dollar bills"
Since she has 5 times as many $20 bills as $5 bills, that means the number of $5 bills is 1/5 number of $20 bills.
The number of $5 bills is 1/5 of x, or x/5.
x number of $20 bills are worth 20x. x/5 number of $5 bills are worth 5 * x/5, or x. The total worth of her bills is 20x + x.
The total worth of her bills is $945.
That means that 20x + x must equal $945. That gives us the equation:
20x + x = 945
b)
20x + x = 945
21x = 945
Divide both sides by 21.
x = 45
x is the number of $20 bills, so she has 45 $20 bills.
The number of $5 bills is 1/5 the number of $20 bills.
1/5 of 45 is 9. She has 9 $5 bills.
Answer: Delia has 45 $20 bills and 9 $5 bills.