Answer:
362.02
Step-by-step explanation:
You need to find "two-fifths of 30." Of here means multiplication:
![\begin{aligned}\dfrac{2}{5}\cdot 30 &= \dfrac{2}{5}\cdot\dfrac{30}{1}\\[0.5em] &= \dfrac{60}{5}\\[0.5em] &= 12\end{aligned}](https://tex.z-dn.net/?f=%5Cbegin%7Baligned%7D%5Cdfrac%7B2%7D%7B5%7D%5Ccdot%2030%20%26%3D%20%5Cdfrac%7B2%7D%7B5%7D%5Ccdot%5Cdfrac%7B30%7D%7B1%7D%5C%5C%5B0.5em%5D%20%26%3D%20%5Cdfrac%7B60%7D%7B5%7D%5C%5C%5B0.5em%5D%20%26%3D%2012%5Cend%7Baligned%7D)
There are 12 athletes in the club.
30u^2v^3 and 8u^5v is : 2u^2v
Answer:
875
Step-by-step explanation:
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
