2 years ago

10 identical spheres of radius 7cm are to be painted. What is the total area of surface to be painted

Mathematics

1 answer:

IgorLugansk [536]2 years ago

6 0

Answer:

Surface area = 4 π r2 square units

Step-by-step explanation:

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You find 72 coins consisting only of nickels, dimes, and quarters, with a face value of $10.20. However, the coins all date from

Oliga [24]

Answer:

You have found 24 nickels.

Step-by-step explanation:

Let N be the number of nickles, D be the number of dimes and Q be the number of quarters. The number of coins and their face values are given by the following expressions, respectively:

$N+D+Q=72\\0.05N+0.10D+0.25Q=10.20$

As of now we have three variables and two expressions, the final expression needed to solve the linear system is given by the amount offered by the coin dealer:

$10N+20D+15Q=1,060$

Solving the linear system:

$N+D+Q=72\\5N+10D+25Q=1,020\\10N+20D+15Q=1,060\\\\10N-10N+20D-20D+15Q-50Q=1,060-(2*1,020)\\-35Q=-980\\Q=28\\\\5N-10N+10D-10D+25Q-10Q=1,020-720\\-5N+15Q=300\\-5N=300-(15*28)\\N=24$