Marcus said the product of 7/8 x 1& 3/4 equals 9/4. how can you tell his answer is wrong

7/8 x 1&3/4 equals 49/32
u change the mixed value (1&3/4) into and improper question which is 7/4 then multiplication rules apply which is 7/8 x 7/4 which gives 49/32 and u can't simply it further..

The answer is d 18ft