You have been cleaning diesel dispensers for 35 minutes you have completed 6 dispensers how many minutes has it taken you to clean 1 dispenser

35/6 = 5.83 minutes <===

The fraction 90/100 is equivalent 1 to 9/10.The fraction 90/100 This is a PROPER FRACTION once the absolute value of the top number or numerator ( 90) is smaller than the absolute value of the bottom number or denominator (100) 
This fraction 90/100 is equal to 90÷100 and can also be expressed in decimal  form as 0.9