Question 74953

Let x=number of fruit flies---they have 6 legs
And y=number of tarantulas-----they have 8 legs

Now we are told that:

x+y=75------------------------------eq 1 (subtract y from both sides)
x=75-y


We are also told that:

6x+8y=562-----------------------------eq 2

We will solve by substitution.  Substitute x=75-y from eq 1 into eq 2

6(75-y)+8y=562  get rid of parens
450-6y+8y=562 subtract 450 from both sides

450-450-6y+8y=562-450  collect like terms
2y=112  divide both sides by 2

y=56-------------------------------------------# of tarantulas

substitute y=56 into eq 1

x+56=75  subtract 56 from both sides
x=75-56
x=19-----------------------------------------# fruit flies

ck

19*6+56*8=562
114+448=562
562=562



Hope this helps -----ptaylor