suppose y varies directly with X, and Y = 22 when x = 8 what is the value of y when x = 10

Use K=y/x

K=22/x

K=22/8

then simplify

K=11/4

27.5

22 = K (8)

Divide 8 on both sides to get your K value

2.75 = K

Plug your K value into the other equation

Y = 2.75 (10)

Solve to get Y

Y = 27.5 When the problem asks "vary directly", it is saying that you are multiplying your K value with your X value (K*X). If the problem is asks "vary indirectly", it is saying that you are dividing your K value by your X value (K/X)