Last year billy weighed 75kg. this year he weighed 90kg. with what percentage did his weight increase. show all !

well let's round. 90= 100, 75=80 that is how I face it. now 80 is 1/5 of 5/5= 100. so as a (%) we would sort it like it is 80% out of +100 so he must have grown around 13%-16% due to him being 75kg in the past.

the entire expression should be subtracted from 30. to subtract the quantity, distribute the negative sign, which changes the signs on the terms. so, the –2 changes to positive and gets added to 30 instead of subtracted from it.

hope this ! ^w^

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)