Triangular prism will be your answer
Answer:
38= 2×19
39= 3×13
40= 2×2×2×5
hcf = highest common factor = 1
if you can't seen any common factor then write 1 , it's common in all.
if all the number divide by same number, then it's common in factor
x/3 + x/5 = 1 hr
8x/15 = 1 hr
x = 15/8
15/8 times 2 for round trip. 15/4 miles or 3.75 miles total
So you have 9x-10 and x= -5
9(-5)-10
-45-10= -55
Your answer would be -55