It is known that a particular project can be completed by nine employees working eight hours a day for twenty five days. To speed completion of the project in a particular town, the supervisor is being provided with twelve workers, and is being asked to complete the project in fifteen days. How many hours a day must the employees worl each day, in order to finish on time?

In order to wipe out the whole job, it takes

(9 persons) x (8 hours/day) x (25 days)  =  1,800 person-hours .

12 workers working for 15 days will accomplish

(12 persons) x (H hours/day) x (15 days)  =  180H person-hours  of work.

180H person-hours  =  1,800 person-hours

H = 10

The 12-person team must work 10 hours/day to make this scheme all work out.  

What'll really happen:  

-- In order to keep tabs on the project and make sure it gets done on the accelerated schedule, the managers in Chicago in suits will assign the supervisor to complete the project in 14 days instead of 15, and they'll require him to send them a status report twice each day.

-- After completing and emailing the Noon status report each day, the supervisor will put on his hard-hat and PPE, and head out to work alongside the 12 sweating workers, who will all begin to sag when they pass 9 hours each day.

-- Day #12 will be solid torrential rain, and no progress will be possible.  The men will want to get some rest, but Chicago will call a Zoom meeting to deliver a motivational pep-talk. Attendance will be mandatory.

-- Days #13 and #14 will stretch to 12 hours, but the project will finish in the allotted 14 days.

-- On Day #15, in Chicago, the customer will treat the managers to a fine dinner, drinks, and a Bulls game, in appreciation for completing the project in 15 days.  In the field, the supervisor and the 12 workers will get to sleep in for a whole hour later than usual, before they clean up the job site and begin the long drive home.

(Been there. Done that.)

d. bc = 12 and ef = 16

step-by-step explanation:

we are given that δabc : δdef such that .

also, it is given that

so, from the options, we need that .

a.

b.

c.  

d.

as, we can see that only option d gives the same ratio as i.e. .

hence, the possible lengths are bc = 12 and ef = 16.

no not all of them.

step-by-step explanation:

some of them have a square base.