Answer:
a) Her reasoning is wrong because √50 does not simplify to 2√25, it simplifies to 5√2. With her thinking that √50 simplifies to 2√25, then this leads to her doing 2 * 5 which equals 10.
b) To estimate a square root, you have to find two square numbers that make the number lie in between the two squares. In this case we need to find two square numbers where one square number is smaller than 50 and the other one is bigger. You should have found the two square numbers to be 7 and 8 because 7² = 49 and 8² = 64. Now we divide 50 by either number, either 7 or 8. As we can't use a calculator it is easier to divide 50 by 8 than 7. 50/8 = 6.25 Now we find the average of 6.25 and 8 which is 14.25/2 = 7.125 7.125 rounded to the nearest tenth is 7.1 Therefore the answer for b is 7.1