Nora swims several times a week in a lake near her house. This past summer, the average water temperature was 24 °C, which is 20% warmer than it was last summer. What was last summer's average water temperature?

Solution

N or a s w im s se v er a l t im es a w ee k in a l ak e n e a r h er h o u se . T hi s p a s t s u mm er, t h e a v er a g e w a t er t e m p er a t u re w a s 24 ° C, w hi c h i s 20% w a r m er t han i t w a s l a s t s u mm er . Wha t w a s l a s t s u mm e r^{'} s a v er a g e w a t er t e m p er a t u re ?

Amount before addition : 20

Solution steps

Translate the problem into an equation:

24 = x + 0.2 x

24 = x + 0.2 x : x = 20

Amount before addition : 20