Ajar contains n nickels and d dimes. there is a total of 278 coins in the jar. the value of the coins is $18.00. how many nickels and how many dimes are in the jar?

Rick is driving to his uncles house in greenville,which is 120 miles from ricks town .after covering x miles rick she's a sign stating that greensville is 20 miles away. which equation when solved will give the value of x. a: x+120 = 20 b: x x120 =20 c: x +20 equals 120 d: x x20= 120