Mo is buying valentine's day cards for the class. There are 30 students and he wants to give a Valentine to 60% of them. They cost $2 each. If he has $40, what percentage of his money will he spend on Valentine?
He needs 18 valentine's cards because 30 x .6 = 
<gadget id="calculator">30*.6</gadget>
<output>18</output>
18.
He will spend $36 on these because 18 x 2 = 
<gadget id="calculator">18*2</gadget>
<output>36</output>
36.
The proportion of his income spent is .9 because 36 / 40 = 
<gadget id="calculator">36/40</gadget>
<output>9/10 = around 0.9</output>
.9.
This is 90% of his income because .9 x 100 = 
<gadget id="calculator">.9*100</gadget>
<output>90</output>
90.

<result>90</result>