Question 938086
Let B = number of bicycles
Let T = number of tricycles
-------------------------
Both types only have two pedals each.
So 36 total pedals divide by 2 mean there are only 18 devices in the museum.
-------------------------
Lets write a couple equations.
Equation 1: {{{B + T = 18}}}
Equation 2: {{{2B + 3T = 43}}}
-------------------------
Solve equation 1 for one of the variables.
{{{B + T = 18}}}
{{{B = 18 - T}}}
Plug (18-T) into equation 2 for B
Equation 2: {{{2B + 3T = 43}}}
{{{2*(18-T) + 3T = 43}}}
Simplify
{{{36 - 2T + 3T = 43}}}
Combine like terms.
{{{36 + T = 43}}}
Subtract 36 from both sides.
{{{highlight(T = 7)}}}
There are 7 tricycles in the museum.
----------------------------------
You can now solve for B as well by plugging 7 in for T
{{{B = 18 - T}}}
{{{B = 18 - (7)}}}
{{{highlight_green(B = 11)}}}