Doug split a pack of cards so that he and his friends each got 6 cards. If there were 24 cards in the pack, how many friends did
1 answer:
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Answer:
The number of nickels is 45 and the number of dimes is 72.
Step-by-step explanation:
Let
x ----> number of nickels
y ----> number of dimes
Remember that
so
------> equation A
------> equation B
<em>Solve the system by substitution</em>
we have
------> equation A
------> equation B
Multiply both equations by 100 both sides
---->
--> equation C
----> equation D
substitute equation C in equation D
solve for y
Find the value of x
<em>Alternative Method</em>
Solve the system by graphing
Remember that the solution is the intersection point both graphs
using a graphing tool
the solution is the point (45,72)
therefore
The number of nickels is 45 and the number of dimes is 72.
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:
