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simultaneous equations

A knife is three times the cost of a spoon
9 spoons and 12 knives cost £82.80
work out the cost of 1 knife
In working ,let k be the cost and s be the cost of the spoon

(edited 3 years ago)

Reply 1

sigma_108

I'm guessing you want some help solving it and are not just posting it up as a problem for others as fun...? lol.. okay so you can start by forming the equations you need:
k = 3s (Using the fact that a knife is 3 times the cost of a spoon)
12k + 9s = 82.80
Now, you can substitute the first expression into the second one to get everything in terms of s and then once you have s, you can easily find k.

Reply 2

Quady

Original post by Bella1525

A knife is three times the cost of a spoon
9 spoons and 12 knives cost £82.80
work out the cost of 1 knife
In working ,let k be the cost and s be the cost of the spoon