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# At billy's school they have some bikes and some trikes with a total of 57 wheels. the number of bikes is three less than three times the num

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At billy's school they have some bikes and some trikes with a total of 57 wheels. the number of bikes is three less than three times the number if trikes. How many bikes and trikes are there?

Guest Feb 27, 2015

#1
+27228
+5

b = number of bikes,  t = number of trikes

2*b + 3*t = 57       wheels

b = 3*t - 3

Substitute the 2nd equation into the first

2*(3*t - 3) + 3*t = 57 or

9t - 6 = 57 or

9t = 63  or

t = 7

Put this back into the 2nd equation;

b = 3*7 - 3 or

b = 18

So, in total: b + t = 25

.

Alan  Feb 27, 2015
#1
+27228
+5

b = number of bikes,  t = number of trikes

2*b + 3*t = 57       wheels

b = 3*t - 3

Substitute the 2nd equation into the first

2*(3*t - 3) + 3*t = 57 or

9t - 6 = 57 or

9t = 63  or

t = 7

Put this back into the 2nd equation;

b = 3*7 - 3 or

b = 18

So, in total: b + t = 25

.

Alan  Feb 27, 2015