Answer: Valentina measured incorrectly.
Step-by-step explanation: 1 feet equals to 12 inches. If you substitute this value for all the other values like 5 ft and 8 inches (Noah's measurement). Firstly, 5 multiplied by 12 is 60, then you would add 8 to it. Caleb already measured the same amount of inches as Noah so we can just leave that one. Same with Mary, 3 * 12 inches = 36 plus 32 which is also 68. Finally, we are left with Valentina in which she has 2 * 12 inches =24 plus 48 which is 72, not 68. Hence, Valentina measured incorrectly.