Question

the ratio of 10 to pencil is 2/7 if you count 84 pencil how many pain would you expect to find

Answer 1

how much pain would you find?   hopefully none, since you'd have lots of pens and pencils :).

$\bf \cfrac{pens}{pencils}\qquad \cfrac{2}{7}\qquad 2:7\qquad \qquad \cfrac{\stackrel{pens}{p}}{\stackrel{pencils}{84}}=\cfrac{2}{7}\implies p=\cfrac{84\cdot 2}{7}$