Bilawal can build a wall in 15 days and Bilal in 20 days. If the work on it together for 4 days , then the fraction of the work ?
A 1/15 wall / day
B 1/20 wall / day
together 1/15 + 1/20 = 7/60 wall/day
times 4 days = 28/60 = 7/15 wall
To determine the fraction of the work completed, we need to find the combined work done by Bilawal and Bilal in 4 days.
Let's start by finding the individual work rates of Bilawal and Bilal:
Bilawal's work rate = 1 wall / 15 days = 1/15 wall per day
Bilal's work rate = 1 wall / 20 days = 1/20 wall per day
Since they are working together, their combined work rate is the sum of their individual work rates:
Combined work rate = 1/15 wall per day + 1/20 wall per day = (4/60) + (3/60) = 7/60 wall per day
By working for 4 days, the amount of work completed is given by:
Work completed = Combined work rate * Number of days = (7/60) * 4 = 28/60 = 7/15
Therefore, the fraction of the work completed by Bilawal and Bilal in 4 days is 7/15.
To find the fraction of the work completed by Bilawal and Bilal in 4 days, we need to consider their individual work rates.
Let's assume that the total work is represented by "1" (since we are finding the fraction of the work completed).
Bilawal can complete the entire work in 15 days, which means he can complete 1/15th of the work in one day. Similarly, Bilal can complete 1/20th of the work in one day.
Since they have worked together for 4 days, we need to calculate the combined work done by both Bilawal and Bilal.
In one day, Bilawal completes 1/15th of the work, so in 4 days, he completes 4/15th of the work.
Similarly, in one day, Bilal completes 1/20th of the work, so in 4 days, he completes 4/20th or simply 1/5th of the work.
Now, to find the combined fraction of the work completed by both of them, we need to add their individual fractions.
4/15 (completed by Bilawal) + 1/5 (completed by Bilal) = (4/15) + (1/5) = 20/75 + 15/75 = 35/75.
Therefore, the fraction of the work completed by Bilawal and Bilal working together for 4 days is 35/75, or simplifying it further, 7/15.