Add the smaller measurement first, which in this case is inches. So you should have 19in. Then add feet, 14ft. Currently we have 14ft and 19in. But 19in can be simplified, since 12in is one foot. So take one foot out of 19 in and you have 7inches left. Add that one to 14. And in the end you should have 15ft and 7in.
Well let’s see if there’s a least common multiple of 5 and 8. Since 40 is the least common mult. We will multiply 40 x .90 and 40 x 1.25 . 40x.90 is 36 while 40x1.25 is 50. It’s better to buy eight pounds for 1.25!