Answer:
The cost of 1 calculator is $28.00
Step-by-step explanation:
You haven't mentioned the question. Anyways if you want to find the value of 1 calculator, the simplest method ( in my opinion) you could do so in the ratio method:
5 calculators : $140
1 calculators : <em>x</em>
( x is the cost of 1 calculator. You have to find <em>x</em>. )
Cross multiply both the ratios. Multiply 5 with <em>x </em>and 140 with 1.
5<em>x </em>= 140 × 1
5<em>x</em> = 140
Bring 5 to the other makes 140 divided upon 5, as it was multiplied with x.
<em>x</em> = 
<em>x</em> = $28
You could not only find the cost of 1 calculator, but any number of calculators. Just replace the number of calculators with 1 calculator that I have found the cost of.