Xiao Hong is the third from the left, the fourth from the right, the sixth from the right, and the second from the bottom. How many teachers are there

Xiao Hong is the third from the left, the fourth from the right, the sixth from the right, and the second from the bottom. How many teachers are there

(3+4-1)x(6+2-1)
=6x7=42

After cutting the 25 cm long rectangular wood block into two pieces, the surface area has been increased by 12 square centimeters. What is the volume of the cuboid

The increase of the two identical surface areas is 12
One area is 6
So the bottom area is 6
6 * 25 = 150 CC

If you want to build a 6m long, 2.7m wide and 60m thick wall with a 3cm long square, how many small squares do you need?
How many cubes should that be

600 × 270 × 6000 = 972000000 (cm3)
3 × 3 × 3 = 27 (CC)
972000000 △ 27 = 36000000 (pieces)

Car a and car B travel from two places 372km apart at the same time. Car a travels 36km per hour. On the way, car a stops for repair for one hour due to fault, and then stops
Continue driving. As a result, car B meets car a 6 hours after starting. Find the speed of one car

Solution of B x
5×36+6x=372
180+6x=372
6x=192
X = 32 A: 32 km per hour

Factorization of (A's Square AB) + C (a-b)

(a^2-ab)+c(a-b)
=a(a-b)+c(a-b)
=(a-b)(a+c)

Party A and Party B move at a constant speed of 2 meters per second and 10.8 kilometers per hour respectively. Party A is 20 meters in front of Party B. can party B catch up with Party A
If so, how long will it take?

The unit conversion problem, 10.8km/h = 10800m / h = 180m / s, compared with 2m / s, can obviously catch up and then solve the pursuit problem equation. Let B catch up with a in T series equation 180 * t = 20 + 2 * t, and solve t = 0.1123s

5A × 5b-5a ／ 5b-5a ／ 5b-5a ／ 5b-10a ／ 5b-5a × 5B find a + B = ()
A = (b =) is also calculated.
（5a）×（5b）－（5a）÷（5b）－（5a）÷（5b）－（5a）÷（5b）－（10a）÷（5b）－（5a）×（5b）＝－10
a＋b＝15 a＝（ ） b＝（ ）

Take a closer look. Is it wrong? I can't do it

The fast and slow trains run from a and B to each other respectively. The slow train takes 8 hours from a to B, which is 1 / 3 longer than the fast train from B to A. if the two trains leave at the same time, the fast train will travel 48 kilometers more than the slow train when they meet. The distance between a and B can be calculated

The time ratio of fast train to slow train is 1: (1 + 1 / 3) = 3:4,
If the distance is the same, the speed is inversely proportional to the time;
When they meet, the express train takes 4 / (4 + 3) = 4 / 7 of the whole journey, and the slow train takes 1-4 / 7 = 3 / 7 of the whole journey,
Therefore, the distance between a and B is 48 (4 / 7-3 / 7) = 336 km

The square of (2a-3b) and the square of - (2a + 3b) can be calculated in two ways

Method 1: (2a-3b) & sup2; - (2a + 3b) & sup2; = 4A & sup2; - 12ab + 9b & sup2; - (4a & sup2; + 12ab + 9b & sup2;) = - 24ab method 2: (2a-3b) & sup2; - (2a + 3b) & sup2; = (2a-3b + 2A + 3b) (2a-3b-2a-3b) = 4A * (- 6B) = - 24ab

A car from city a to city B completes 1 / 4 of the whole journey in the first hour, and 20% of the whole journey in the second hour. At this time, it is 9km away from the destination, and the distance between city a and city B is? Km

9÷(1-1/4-20%)
=9÷11/20
=180/11