Problema Solution
I have 25 coins in my pocket all of which are 5 cent or 20 cent coins. If their total value is $2.90 how many 5 cent coins do I have
Answer provided by our tutors
1. Simply form 2 equations that represent this scenario.
5x + 20y = 290
x + y = 25
where x and y are the number of 5 cents and 20 cents coins respectively.
Now just solve the simultaneous equations,
Rearranging equation 2 gives,
x= 25 - y
Substituting into equation 1 gives,
5(25-y) + 20y = 290
125 - 5y + 20y = 290
15y = 290 - 125
y = 165/15
y = 11 So you have eleven 20 cents coins.
Plugging this back into equation 2 gives,
x + 11 = 25
x = 25 - 11
x = 14 So you have fourteen 5 cents coins.