A school bought pens, each costing $1, and pencils, each costing $0.5. The cost of the whole purchase was $220. How many pens and pencils were purchased if there were 80 more pencils than pens?

120 pens and 200 pencils

Step-by-step explanation:

Let the cost of pens be x and for pencils be y

Given that a pen costs $1 and a pencil is $0.5 then the total cost is $220, the equation will be

x+0.5y=220

Also, since pencils were 80 more than pens, it means y-x=80

0.5y+x=220

y-x=80

Add the equations

1.5y=300

y=300/1.5=200

Since y-x=80

200-x=80

x=200-80=120

Therefore, there were 120 pens and 200 pencils

2

step-by-step explanation:

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7 weeks

step-by-step explanation:

convert each fraction to the least common multiple of 20, so 3/4 = 15/20 & 1/10 = 2/20, then divide 15 by 2 and you get a little over 7, so the food will last 7 weeks.