Alvin's Blog Post

Today in math we were each assigned a question from the textbook. My question was in section 2.2, on page 60 question #13.

The question was :
A submarine was cruising at a depth of 153m. It then rose at 4.5m/min for 15 minutes.

a) What was the submarine's depth at the end of the rise ?

Since the submarine was rising 4.5m/min for 15 minutes, all you need to do is multiply the meters by the minutes. Because since 1 minute is 4.5m then if it were 15 minutes you multiply the minutes by 15, and what you do to one side you have to do the same to the other. So 4.5/1 x 15/1 = 67.5, the submarines depth at the end of the rise would be 85.5 since then you have to subtract that distance from the total distance ( 153 - 67.5 = 85.5).

b) If the submarine continues to rise at the same rate, how much longer will it take to reach the surface ?

Since the submarine is already at 85.5m you have to find the amount of time it will take the submarine to surface. So you divide the distance by the amount of time it takes to rise, so then its 87.5 divide 4.5 = 19. You do that because if 4.5m is a minute, and you want to find how many minutes it takes to rise 85.5 you divide those numbers. So then the submarine will take 19 more minutes to reach the surface.

Thanks for reading my blog, I couldn't put color in for some reason.