Answer: 0.87 g of an 8% w/w progesterone gel must be mixed with 1.45 g of a 4% w/w progesterone gel to prepare a 5.5% w/w gel.
Explanation:
According to the dilution law,
where,
= concentration of ist progesterone gel = 8%w/w
= weight of ist progesterone gel = x g
= concentration of another progesterone gel = 4% w/w
= weight of another progesterone gel = 1.45 g
= concentration of resulting progesterone gel = 5.5%w/w
= weight of resulting progesterone gel = (x+1.45) g
Thus 0.87 g of an 8% w/w progesterone gel must be mixed with 1.45 g of a 4% w/w progesterone gel to prepare a 5.5% w/w gel.
solution:
You need to find the frequency, and they have already given you the wavelength. And since you already know the speed of light, you can use formula (2) to answer this problem. Remember to convert the nano meters to meters because the speed of light is in meters. 
Polluted water. The growing crops and climate variability change. Basically the farming
