Question 1122977
Five brothers bought a gift for their mother’s birthday.
The cost of the gift was 150 dollars. 

Moses gave 80 dollars, 
<pre>
So Moses' contribution = $80
</pre>
Daniel gave 21 dollars,
<pre>
So Daniel's contribution = $21
</pre>
Anthony gave 20%, 
<pre>
Since 20% of $150 = (0.20)×($150) = $30, 
So Anthony's contribution was $30
</pre>
Lucas gave 18 dollars 
<pre>
So Lucas' contribution was $18
</pre>
and Mark paid the rest. How much was Mark´s contribution?
<pre>
We add the contributions from Moses, Daniel, Anthony and Lucas:

 $80 Moses
  21 Daniel
  30 Anthony
 +18 Lucas
----
$149 Total contribution from other four besides Mark

Then we subtract

$150
-149
----
$  1 the amount Mark contributed, just one dollar!

Edwin</pre>