It is quite common question asked in the Speed chapter. A bit twist, rather than DISTANCE, now it is asking JOB.
Example:
John, Mark, and Shaun were hired to paint a house.
Together, they can finish the job in one hour.
John and Mark can finish the job in 1 hour 12 minutes.
Mark and Shaun can finish the job in 1 hour 30 minutes.
How long in minutes will Mark take to finish the same job by himself ?
Mr. Loh had some sneakers in his shop. 3/8 of them were red, 3/10 of the remainder were black, and the rest were white.
The table above shows the amount he earned per pair of shoes. The number of red shoes sold to the number of black shoes sold to the number of white shoes sold was 1 : 2 : 4. In total, he sold one quarter of the shoes and earned $1,080. How many pairs of white shoes did have at first ?
In a bakery, the ratio of the number of cupcakes to the number of beef pies was 4:5. When 5/8 of the cupcakes were sold and another 12 beef pies were added on the shelf, the new ratio of cupcakes to beef pies was 1:4.
(1) How many cupcakes were eaten?
(2) How many cupcakes and beef pies were there at first?
On the MRT, the ratio of men to women was 2 : 1.
At Orchard Station, one fifth of the men and some women alighted from the train. The ratio of men to women became 8 : 1. At Newton Station, 20 men and 160 men boarded the train. There were the same number of men and women left the train.
(a) How many passengers were there in the train after Newton Station?
(b) How many women alighted from the train?
