Arman is six times older than his sister. His sister is 2 years old four years ago. In how many years will Arman's age be 40?
Arman's sister is 4 + 2 = 
<gadget id="calculator">4+2</gadget>
<output>6</output>
6 years old now.
So, Arman is 6 x 6 = 
<gadget id="calculator">6*6</gadget>
<output>36</output>
36 years old.
Hence, Arman will be 40 in 40 - 36 = 
<gadget id="calculator">40-36</gadget>
<output>4</output>
4 years.

<result>4</result>