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# Help Zone

### Student Question

Secondary II • 3mo.

Hi can someone help with this math question please

Mathematics

## Explanations (1)

• Explanation from Alloprof

Explanation from Alloprof

This Explanation was submitted by a member of the Alloprof team.

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Team Alloprof • 3mo.

Hi 😊

You have to use inequalities to solve.

x : number of lamps that have an electrical defect

y : number of lamps that have an optical defect

z : number of lamps that have both defects

200 - 180 = 20

20 lamps have at least one defect.

x < 16

y < 12

x + y + z = 20

You have to resolve :

If you substract one lamp of each variable (x and y), you add one to z.

Try with :

x = 15

y = 12

z = 1

You have :

x + y + z = 20

15 + 12 + 1 = 28 20

You have to continue.

x = 10

y = 8

z = 6

x + y + z = 20

10 + 8 + 6 = 24 20

Again!

x = 6

y = 4

z = 10

x + y + z = 20

6 + 4 + 10 = 20

We did it! 😎

So, we have :

x = 6 lamps that have an electrical defect

y = 4 lamps that have an optical defect

z = 10 lamps that have both defects

Hope this helped! 😁 Read you soon on the Help Zone 🥴