The head teacher of a class in a school leads the students to travel. A travel agency says, "if the teacher buys a full ticket, the student ticket can be 50% off.", B travel agency said: "including teachers, all according to the full fare discount", assuming that the full fare of 240 yuan / piece (1) If there are X students, please write down the algebraic formula of the expenses of travel agencies a and B (2) If there are 10 students, which travel agency will you follow to save money (3) When there are many students, the cost of the two travel agencies is the same

The head teacher of a class in a school leads the students to travel. A travel agency says, "if the teacher buys a full ticket, the student ticket can be 50% off.", B travel agency said: "including teachers, all according to the full fare discount", assuming that the full fare of 240 yuan / piece (1) If there are X students, please write down the algebraic formula of the expenses of travel agencies a and B (2) If there are 10 students, which travel agency will you follow to save money (3) When there are many students, the cost of the two travel agencies is the same

Because the full price ticket is 240 yuan, so (1) a: 240 + 0.5 × 240x = 240 + 120x, B: 0.6 × 240 (x + 1) = 144 + 144x
(2) When there are 10 students, travel agency a needs 240 + 120 × 10 = 1440 yuan, travel agency B needs 144 × (10 + 1) = 1584 yuan, so travel agency a saves money
(3) When 240 + 120x = 144 + 144x, x = 4

****There are 100 primary school sixth grade students who have reached the standard of physical education, and there are 25 students who have not reached the standard______ %．

100 100 + 25 × 100%, = 100 125 × 100%, = 80%; a: the rate of reaching the standard is 80%