15 decreased by the quotation of a number and 3 is 20

15 - n/3 = 20

n = - 15

Step-by-step explanation:

Decreased means subtract

15 -

quotient means divide

15 - n/3

Is means equals

15 - n/3 = 20

To solve subtract 15 from both sides

15-15 - n/3 = 20-15

-n/3 = 5

Multiply each side by - 3

-3 * (-n/3) = 5*-3

n = - 15