calculate the atomic mass of an element if 60.4% of the atoms have a mass of 68.9257 amu and the rest have a mass of 70.9249 amu.

Which food would provide you with the most calcium?

Abag contains even and odd numbered balls in the ratio of 3: 7, respectively. for each of the following, what is the probability of drawing an even-numbered ball? the total number of balls is 240 and 30 of the odd-numbered balls are renumbered by multiplying the numbers by 4.

How many liters of 60% alcohol solution should be added to 40 liters of a 20% alcohol solution to make a 50% solution?