Solution for yesterday’s problem
The nth term of arithmetic progression = a+(n-1)d, where a is first term, d is common difference, and n is number of terms.
By supposition, 121+(n-1)*-4<0
-4n<-125 or 4n>125 => n>31.25
A trader buys goods for $450. He sold one-third of it at a loss of 10%. At what profit percent should the remaining goods be sold so as to gain 20% overall?