Will mark the correct answer brainliest

Gabriel determined that his total cost would be represented by 2.5x + 2y – 2. his sister states that the expression should be x + x + 0.5x + y + y – 2. who is correct? explain.

The ideal weight of a nickel is 0.176 ounce. to check that there are 40 nickels in a roll, a bank weighs the roll and allows for an error of 0.015 ounce in total weight

Summary statistics given for independent simple random samples from two populations. use the pooled t-interval procedure to obtain specified confidence interval. x1=71.6, s1=3.9, n1=11, x2=67.9, s2=3.4, n2=9 determine a 99% confidence level.