Question 627773
You have the right equations, but you are
given 3 unknowns and only 2 equations can
be written, so you have to somehow make
up for the missing equation with logic.
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Notice he spent $45.50. The only way he can 
end up with the 50 cents is if he saw an
odd number of the matinees, or
1,3,5,7,9, or 11 matinees.
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It couldn't have been 11 matinees, since
{{{ 11*4.5 = 49.5 }}} which is too much
It can't be 9 either since
{{{ 9*4.5 = 40.5 }}} and
{{{ 40.5 + 3 + 7 = 50.5 }}} already too much
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I'll try 7
{{{ 7*4.5 = 31.5 }}}
{{{ 31.5 + 3 + 7 = 41.5 }}} too low
Can't get an extra 4 to make it 45.5,
so it can't be 7
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I'll try 5
{{{ 5*4.5 = 22.5 }}}
{{{ 22.5 + 3 + 7 = 32.5 }}} low
{{{ 22.5 + 3 + 14 = 39.5 }}} low
{{{ 22.5 + 3 + 21 = 46.5 }}} high
{{{ 22.5 + 6 + 14 = 42.5 }}} low
{{{ 22.5 + 18 + 14 = 54.5 }}} high
I'll try 3
{{{ 13.5 + 18 + 14 = 45.5 }}} OK
So {{{ 3*4.5 + 6*3 + 2*7 = 45.5 }}}
He saw 3 matinees, 6 rentals, 2 evening movies
So, some logic and some guessing works