The cost of 18 pens is rs. 150 . find the cost of 66 such pen

In a certain pentagon, the interior angles are a, b,c, d,e where a, b,c, d,e are integers strictly less than 180. ("strictly less than 180" means they are "less than and not equal to" 180.) if the median of the interior angles is 61 and there is only one mode, then what are the degree measures of all five angles?

Average acceleration: i have no idea how to do this.

X2 + y 2 = 36 x + y = 6 solve the system of equations.