To solve this formula for T, divide both sides of the original equation by PR:
I PRT
------ = --------- => T = I / (PR)
PR PR
Please note: Because the formula I = PRT involves neither addition nor subtraction, the final formula for T cannot involve either addition nor subtraction. That leaves:
T = I P/R
T= IPR
The second formula here is incorrect; we cannot solve I = PRT for T simply by rearranging the order of the variables. This leaves T = I P/R as a possible answer, but this answer does not agree with my T = I / (PR). Please double check to ensure that you have copied down the four possible answers correctly.