There is a big boat and a small boat (A and B are natural numbers).
3a+2b=20
Try to calculate: a=6, b= 1 is the most economical.
1, because the unit price of big ships is cheap, rent as many big ships as possible;
2. Try to have as few empty seats as possible, and finally there are no empty seats.
6×8+ 1×6=48+6=54 (yuan)
Answer: It is the most economical to rent 6 boats and 1 boat, and 54 yuan is the most economical.
Calculation rules of multiplication:
Number alignment, starting from the right, multiply the first factor by the number on each bit of the second factor, and the end of the number will be aligned with which bit of the second factor.
The digits of two numbers are the same, while the digits of ten are complementary.
(1) Multiplies the first digit of two numbers and adds the numbers.
(2) The mantissa of two numbers is multiplied (less than ten, and ten digits add up to 0). Formula: head joint, tail to tail.