Answer is 3 1/10
6 1/2 - 3 2/5 =
13/2 - 17/5 =
65/10 - 34/10 =
31/10 = 3 1/10
Transitive property is your answer
if ∠A ≅ ∠C, and ∠C ≅ ∠B then, ∠A ≅ ∠B
hope this helps
You have two totals: total # of bills and total amount of $. Using x as #of 20s, and y as # of 50s, you can use the system
x+y=18
20x+50y=450
This is
{HH, TT, TH, HT} where H = head and T = tail