6. A form of the element actinium, Ac-225, has a half-life of 10 days. At the end of an experiment that lasted 40 days, there were 2 grams of Ac-225 left. How much Ac-225 was there at the beginning of the experiment? a. 2.2.1012 grams c. 0.125 grams b. 32 grams d. 16 grams explain​

in problems involving proportions, we can use cross products to test whether two ratios are equal and form a proportion. to find the cross products of a proportion, we multiply the outer terms, called the extremes, and the middle terms, called the means.

hope it

step-by-step explanation:

if you are looking for the unit rate then the answer would be 9 because unit rate is distance divided by time.

step-by-step explanation:

answer:   expression= p+p*d%

price reduction + sale price = $625

sale price: $p+$p*d%

where d% is the percentage of discount

step-by-step explanation:

original price = p

price went down by $150 price reduction $p*d%

sale price= $ 475

therefore the price before sale is: $625

and the expression that shows the price before sale is: p+p*d%