The second survey is more believable because there is randomness in the second rather than the first survey. Since the second company surveyed in all interest levels while the first company only surveyed their best customers. Random sampling like what the second company did helps produce representative samples by removing voluntary response bias and undercover age bias.
Looks like you are missing a fraction after the 'If'
Finding the volume of this will mean that we'll have to know the formula. The formula for finding the volume of a prism is L x W x H.
L- Lenght
W - Width
H - Height.
So Volume is going to be equalled to 6 x 5 x 4 = 120 cm cubed
I think Its 66 cm. Hope This Helped! Good Luck...