Select the correct answer. the sum of sally and beth's age is 60. six years ago, sally was 3 times as old as beth. what are their present ages? a. beth's age is 15 years, and sally's age is 45 years. b. beth's age is 18 years, and sally's age is 42 years. c. beth's age is 42 years, and sally's age is 18 years. d. beth's age is 45 years, and sally's age is 15 years.

B. Beth's age is 18 years, and Sally's age is 42 years.

Step-by-step explanation:

You can solve this question in a couple of different ways. First, you can use process of elimination. You know that Sally is older than Beth because she has to be 3 times older 6 years ago, so you can get rid of options C and D because they both show Beth as being older. Now you only have A and B, and you can use a different process. Now from just looking at it, you can tell that A actually already shows Sally as 3 times Beth's age, 15 * 3 = 45. If you go to B, you can go ahead and subtract 6 from 18 (Beth's age) which will give you 12, and then multiply that by 3 to get 36. Now if you take 42 (Sally's age) and subtract 6 from it as well, you will get 36. This means that is lines up. To simplify, you are subtracting 6 from both 18 and 42, and then you are multiplying the lower number by 3 to see if it gets to the bigger number.

Hope this helped ^-^

step-by-step explanation:

step-by-step explanation:

the original amount doesn't ''re just looking for the time it takes for 1/2 of the substance to we have

(1/2) =)     take the ln   of both sides

ln (1/2)   = )   and we can write

ln(1/2) = ) lne     and lne   = 1     so we have

ln(1/2) = -.1092t     divide both sides by -.1092

t = ln(1/2)/-.1092 = about 6.347 days = about 6.3 days (rounded)