Answer:
40% of the number is 275.2.
Explanation:
I am going to call the number x.
75% of the number: 0.75x
20% of the same number: 0.2x
The difference between 75% of a number and 20% of the same number is 378.4:
This means that:
0.75x - 0.2x = 378.4
0.55x = 378.4
x = 378.4/0.55
x = 688
40% of the number:
0.4*688 = 275.2
40% of the number is 275.2.