At the senior sports meeting, Liu Dabo took part in the long-distance race, which took 9.7 minutes to finish the race. How many minutes does Li Dabo need to run a kilometer? (Li Dabo takes 2 minutes more than Liu Dabo). The teacher said (9.7 + 2) * 1.5 = 7.8 minutes. Why?

At the senior sports meeting, Liu Dabo took part in the long-distance race, which took 9.7 minutes to finish the race. How many minutes does Li Dabo need to run a kilometer? (Li Dabo takes 2 minutes more than Liu Dabo). The teacher said (9.7 + 2) * 1.5 = 7.8 minutes. Why?

9.7 + 2 is the time used by Uncle Li
It takes 9.7 + 2 minutes to run 1.5km. Divide 1.5km into 3 parts, 0.5km for each part, 2 parts is 1km, so running 1km takes 2 / 3 of the total time, that is 1.5, so (9.7 + 2) * 1.5 = 7.8 is the time used@
I wish you progress in your study@

A math problem in grade one of junior high school
There are four numbers 3, - 5,7 and - 13 to calculate 24
Come on

[(-5)×(-13)+7]÷3=24

Decomposition factor M + 5n-mn-5m

Decomposition factor M + 5n-mn-5m
m +5n-mn-5m= m -5m -mn+5n
= (m -5m )+(-mn+5n)
=m(m-5)-n(m-5)
=(m-5)(m-n)

A simple algorithm for (873 * 477-198) - (476 * 874 + 199)

873*477-198-476*874-199
=873*(476+1)-476*(873+1)-400+3
=873*476-476*873+873-476-400+3
=0

What is the 1 / 4 of this number

5 is 2.5, which means that the number is 4.5
1 / 4 of 4.5 is 1.125

4 / 9 of a certain number is 2.1 more than 1.25 of 1.2. What's the number

(1.2x1.25 + 2.1) △ 4 / 9

The sum of 4 times of a number and 5.5 times of it is 1.9. What is the number?

1.9 △ 4 + 5.5, = 1.9 △ 9.5, = 0.2. A: this number is 0.2

The sum of 4 times of a number and 5.5 times of it is 1.9. What is the number?

1.9 △ 4 + 5.5, = 1.9 △ 9.5, = 0.2. A: this number is 0.2

Under what circumstances is 9 + 4 equal to 1

September plus four months is January

How much is 4 out of 9 times 9 out of 11?

Four out of nine times nine out of eleven equals four out of eleven