A, B and C are friends. They go to the library every other day. A goes to the library every three days, B every four days and C every five days The three of them met in the library. At least how many days later will they meet again in the library?

They'll meet again in the library in at least 60 days
3x4x5 = 60 days

Each of the three children goes to the swimming pool once every other day, once every 2 days for a, once every 3 days for B, and once every 4 days for C
How many days after the last time they met in the swimming pool, will they meet again in the swimming pool?

The least common multiple of 2,3,4 is 3 × 4 = 12
So in 12 days, they will meet again in the swimming pool

Let a and B be m × n matrices, and prove that a and B are equivalent if and only if R (a) = R (b)

It is proved that: (necessary) let a and B be equivalent, then B can be regarded as a matrix obtained by a finite elementary transformation, and the elementary transformation does not change the rank of the matrix, so r (a) = R (b). (sufficient) let R (a) = R (b), then the standard forms of a and B are erooo, that is, a and B are equivalent to erooo, so a and B are equivalent

1 / 3, 1 / 2, 5 / 9, 7 / 12, 11 / 18, 13 / 21. What is the number of 2012 in this column?

4023/6036

The approximate number 13.35 is accurate to () bits; the approximate number 0.018 has () significant digits

Percentile
three

Xiao Hong read a story book. On the first day, she read 45 pages. On the second day, she read 20 more pages than on the first day. How many pages did she read in two days?

45 × (1 + 20%) + 45 = 45 × 120% + 45 = 54 + 45 = 99 (page)

Let - M & # 178; be a, 1-N & # 178; be B, then a-3b is ()

A-3B
=-m²－3(1-n²)
=-m²-3+3n²

A passenger car and a freight car run from a and B at the same time. They meet in 6 hours. After meeting, the passenger car runs for another 4 hours to arrive at B. how many hours does the freight car have to travel to arrive at a?

6 × (6 △ 4), = 6 × 32, = 9 (hours). Answer: at this time, the truck will have to drive for 9 hours to reach a

Log2 (bottom) (x + 1) (true) - log2 (bottom) (2x-1) (true) = 1
Log2 (bottom) (x ^ 2-x) = log2 (bottom) 2 (X-2)
lg^2x+lgx^2-3=0
1/(5-lgx)+2/(1+lgx)=1

Log2 (bottom) (x ^ 2-x) = log2 (bottom) 2 (X-2)
x^2-x=2(x-2)
x^2-3x+4=0
△=9-16

The speed ratio of a and B is 2:3, the time ratio is 6:5, and the distance ratio is 2:3______ ．

(2 × 6): (3 × 5), = 12:15, = 4:5. Answer: the ratio of the distance they traveled is 4:5

A, B and C are friends. They go to the library every other day. A goes to the library every three days, B every four days and C every five days The three of them met in the library. At least how many days later will they meet again in the library?