A few days ago
delamater2001

# Homework help for math. Needed to help son.?

ryan bought 4 pens and 9 pencils and paid a total of \$8.90. Ashleigh purchased 2 pens and 6 pencils and paid \$5.20. Find the cost for a single pen and pencil

A few days ago
dpirsq2

Let x = pens

y = pencils

4x + 9y =\$8.90

2x + 6y = \$5.20 Multiply this equation by -2 so we can eliminate one variable

4x + 9y = \$8.90

-4x – 12y = – \$10.40 The 4x cancels out.

-3y = -\$1.50 Divide by -3

y = \$.50 for each pencil

Now substitute for y to solve for x.

4x + 9(\$.50) = \$8.90

4x + \$4.50 = \$8.90

4x = \$4.40

x = \$1.10 for each pen

To check substitute the values in each equation and it will work.

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A few days ago
hayharbr
Choose a variable for each cost, say x for pen and y for pencil

4x + 9y = 890

2x + 6y = 520 (in cents)

This is how, algebraically. Other ways include guess and check- just guess some prices that work for one equation and see if they work for the other; if not change them until they do. Not very efficient unless you are a lucky guesser though.

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