Why does an even number plus an odd number always equals an odd number?

During a wright loss challenge your friend goes from 125 pounds to 100 pounds.what was the percent weight loss

From a group of 10 men and 8 women, 5 people are to be selected for a committee so that at least 4 men are on the committee. howmany ways can it be done?

$30 to spend on dinner tax and gratuity at mos restaurant rax is 6% and they give a 15% tip on the total bill after taxes thier dinner cost $21 which statement correctly explains wether andrew and kate have enough money to pay their bill