Hi there amathsnovice,

First thing to do is find the percentages/number of employees in the original problem.

Engineers: 4/5 of 180 = 144. This was 80%

Sales: 1/5 of 180 = 36. This was 20%

For the new Sales figure to be 25% then the new Engineers figure should be 75%. Do you follow? So let's find the new total amount given this information. We know there is to be no additional works in the Engineering department therefore we can solve

75% of x = 144. x will be the total number of employees and the new number of Sales will be x-144. Therefore the increase of desired Sales staff will be (x-144)-36.

What do you get?

Next time be mindful of our forum's rules which state you must show your workings and where you are stuck this will maximise the chances of recieveing help.

kind regards,