Please explain in easy way

Isnigro II. For the following problems, work out the new mAs required and give a new mA and time in fraction form that will give you the desired mAs. Remember that it is not always possible to get the exact mAs with the mA and time combinations available on your X-ray equipment. Choose an mA and time that are reasonable for your equipment. (Note that usually there will be more than one reasonable combination from which to select.) Original Ops New Distance Time Distance Time (in) MA (sec) mAs (in) MA (sec) OF 40 100 1/2 44 1