19 × 1.03 = 19.57
The answer is 19.57.
Answer:
5 hours
Step-by-step explanation:
This is a classic pre-algebra question.
Answer: 490 grams of the first alloy should be used.
30 grams of the second alloy should be used.
Step-by-step explanation:
Let x represent the weight of the first alloy in grams that should be used.
Let y represent the weight of the second alloy in grams that should be used.
A chemist has two alloys, one of which is 15% gold and 20% lead. This means that the amount of gold and lead in the first alloy is
0.15x and 0.2x
The second alloy contains 30% gold and 50% lead. This means that the amount of gold and lead in the second alloy is
0.3y and 0.5y
If the alloy to be made contains 82.5 g of gold, it means that
0.15x + 0.3y = 82.5 - - - - - - - - - - - -1
The second alloy would also contain 113 g of lead. This means that
0.2x + 0.5y = 113 - - - - - - - - - - - - -2
Multiplying equation 1 by 0.2 and equation 2 by 0.15, it becomes
0.03x + 0.06y = 16.5
0.03x + 0.075y = 16.95
Subtracting, it becomes
- 0.015y = - 0.45
y = - 0.45/- 0.015
y = 30
Substituting y = 30 into equation 1, it becomes
0.15x + 0.3 × 30 = 82.5
0.15x + 9 = 82.5
0.15x = 82.5 - 9 = 73.5
x = 73.5/0.15
x = 490
Answer:
18.95%
Step-by-step explanation:
In this case what we must do is calculate the probability of eating a jelly treats first and then another jelly treats, being the final probability the multiplication of these events.
We know that there are 20 in total and that initially there are 9 jelly treats, so the first event is the probability:
9/20
And the second event, with one less in each, would be:
8/19
The final probability then:
9/20 * 8/19 = 0.1895
So the probability of this happening is 18.95%
Answer:
<h2>A</h2>
Step-by-step explanation:
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