The numbers of pizza slices that are sold in Joey's Pizza are only in quantities of 5 and 8 slices per customer. How many slices cannot be bought?  Pick one.
A) 42.
B) 38.
C) 33.
D) 22.
E) 20
Let X pizzas of 5 slices and Y pizzas of 8 slices.   5X + 8Y.   Lets check options wise.   A. 42 =&gt; 5(2) + 8(4)   B. 38 =&gt; 5(6) + 8(1)   C. 33 =&gt; 5(5) + 8(1)   D. 22 = we can't write anything with 5 and 8 series..Lets try 5(1) + 8(2) = 21 , 5(3) + 8(1) = 23 , nothing works out.   E. 20 = 5(4) + 8(0)   Answer: correct option is 22.
<result>D</result>
The numbers of pizza slices that are sold in Joey's Pizza are only in quantities of 5 and 8 slices per customer. How many slices cannot be bought?