Point 5 Julisha poured 0.9 liter of water into an
empty flask. She boiled the water for 15
minutes then measured the amount of water
that remained. She found that 80% of the
water remained in the flask. Measured in
liters, how much water evaporated?

First step is to get rid of the square root. remember that a square root is the same as raising to the (1/2) power. see below: multiply exponents per exponent rules to get: remember you subtract exponents from the denominator and add exponents in the numerator so: simplify further: so a is the correct choice. if you don't understand this google exponent rules and it will you understand. look at the image results.