of the questions on his math test, Shane answered 42 correctly and 18 incorrectly what percent of the total questions did Shane answer correctly?

70%

Step-by-step explanation:

Okay so to find out the percent that Shane got correct you first have to find out the number of questions in the test by adding 42 and 18 together. 42 + 18 equals 60. So he got 42/60 questions on his quiz correct. Now we have to turn 42/60 into a decimal by dividing 42 by 60, 42 divided by 60 equals 0.7 Now to turn a decimal into a percent you have to move the decimal 2x to the right. So if we move the decimal in "0.7" twice to the right we get our total percentage of 70. So, in conclusion, Shane got 70% of the answers on his quiz correct.

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)