Question #f9561

3 Answers
Aug 27, 2017

See a solution process below:

Explanation:

We can write an equation using the variable names in the problem as:

#c = b * p#

Where:

#c# is the total cost of the bananas.

#b# is the price per pound for the bananas

#p# is the weight of the bananas.

Substituting from the problem for #c# and #p# we can solve for #b#:

#$2.50 = b * 5"lbs"#

#($2.50)/color(red)(5"lbs") = (b * 5"lbs")/color(red)(5"lbs")#

#($0.50)/("lbs") = (b * color(red)(cancel(color(black)(5"lbs"))))/cancel(color(red)(5"lbs"))#

#($0.50)/("lbs") = b#

#b = ($0.50)/("lbs")#

We can substitute this into the original equation to give us the equation for bananas:

#c = ($0.50)/("lbs") * p#

We can now determine the price for #8"lbs"# by substituting for #p# and calculating #c#:

#c = ($0.50)/("lbs") * p# becomes:

#c = ($0.50)/("lbs") * 8"lbs"#

#c = ($0.50)/color(red)(cancel(color(black)("lbs"))) * 8color(red)(cancel(color(black)("lbs")))#

#c = $4.00#

Mrs. Baker would pay $4.00 for 8 pounds of bananas at the same price.

Aug 27, 2017

This is a ratio. Set up the values in an equation that will give the desired dimensional amount.
#"cost" = $0.50/"pound"#
#$4.00#

Explanation:

In this case, we must first determine the ratio: #"cost"/"pound"#.
This is #"cost" = $2.50/5 "pounds" = $0.50/"pound"#

NOW we can use this ratio to calculate ANY price for any weight of bananas. Applied to the question of how much 8 pounds of bananas would cost, we have:
#$0.50/"pound" xx 8 "pounds" = $4.00#

Aug 27, 2017

#$4#

Explanation:

We first must determine the cost for one pound of bananas.

We can do this by dividing #(2.50)/5=0.5#. So one pound of bananas cost #$0.50#

We can then write a generalized equation:

#C=0.5p#

where #C# is the total cost and #p# is the amount of pounds of the bananas.

We can try out this equation by substituting #5# for #p# in the equation. This should yield #2.50#

#C=0.5(5)#

#C=2.50#

Thus, to answer your other question: To find the cost for #8# pounds bananas, we substitute #8# for #p# in our equation:

#C=0.5(8)#

#C=4#

So Mrs. Baker would pay #$4# for #8# pounds of bananas