For each <em>x</em> in the interval 0 ≤ <em>x</em> ≤ 5, the shell at that point has
• radius = 5 - <em>x</em>, which is the distance from <em>x</em> to <em>x</em> = 5
• height = <em>x</em> ² + 2
• thickness = d<em>x</em>
and hence contributes a volume of 2<em>π</em> (5 - <em>x</em>) (<em>x</em> ² + 2) d<em>x</em>.
Taking infinitely many of these shells and summing their volumes (i.e. integrating) gives the volume of the region:

Answer:
241 tons
Step-by-step explanation:
312-170=142
142÷2=71
170+71=241
241+71=312
train B weighs 241 tons
<u>Part</u><u> </u><u>1</u> 6(1.20)+4(1.05)=$11.40
<u>Part</u><u> </u><u>2</u> 1.20x+1.05y
Answer: C & D
Step-by-step explanation: