Hello!
Let 'a' stand for adult tickets and 'c' for children tickets.
a + c = 15
(Both adult and children tickets make up a total of 15 tickets).
30a + 20c = 330
a = 3
c = 12
A N S W E R:
William bought 3 adults tickets and 12 children's tickets.
So, what is the case in which he uses the least coins? can he use 1 coin? no, there isn't a 35 cent coin. can he use 2 coins? yes! he can use 25+10 cent coins!
now, the largest number of coins means the coins of the smallest value: so using only 5 cent coins. How many would this be?
we have to divide:
35/5=7
so we would use 7 coins.
And the difference is 5: 7-2 is 5.
if its 679 and is on sale for 35% off the price now would be 441.35
For number 10 the y-intercept is going to be at -1 1/3 not -1.
