Question 3. Two neon lights are turned on at the same time. One blinks every 4 seconds and the other blinks every 6 seconds. Answer the following questions, give your answer only.

a) How long will it take them to blink simultaneously for the first time after they are turned on? (simultaneously: at the same time)

a = 6 s

Question 3. Two neon lights are turned on at the same time. One blinks every 4 seconds and the other blinks every 6 seconds. Answer the following questions, give your answer only.

b) How many times will they blink simultaneously in the first 70 seconds after they are turned on?

b) 11

Answer :

A. 27 seeds

# Hok tốt !

Trả lời :
the gratest number should be 45 because she wants to put the same plant in the same row and the same amount of plants in each row 

HT

A. 3 teams

Question 5. The teacher wants to divide 87 students into teams which have the same number of students. Knowing that there must be more than one team, at least how many teams can be formed?

3 teams

answer

a) At least how many packages of cups should she buy? Give your answer only. Answer:  _________ packages

chỗ cần điền là : two

a, 2 packages

A is forty-one

If A is sixteen less than fifty seven, then the value A is...CAT..

Lan ăn nhiều hơn

\(\frac{2}{3}\)< \(\frac{3}{5}\)

Lan ăn nhiều bánh hơn Hùng

40000 nghìn đồng

Gọi số bị trừ là x, số trừ là y \(\left(x,y\in N\right)\)

Ta có: x-y= 6=> x=6+y

Có :4x-y=54 <=> 4.(6+y)-y= 54 <=> 24+4y-y=54 <=> 3y= 30 <=> y=10

=> x= 6+10 =16

a, sinC = \(\frac{AB}{BC}\); tanC = \(\frac{AB}{AC}\)

cosC = \(\frac{AC}{BC}\); cotC = \(\frac{AC}{AB}\)

b, Xét tam giác ABC vuông tại A, đường cao AH

tanB = \(\frac{AC}{AB}=\sqrt{2}\Rightarrow AC=\sqrt{2}AB\)

* Áp dụng hệ thức : \(\frac{1}{AH^2}=\frac{1}{AB^2}+\frac{1}{AC^2}\Rightarrow\frac{1}{12}=\frac{1}{AB^2}+\frac{1}{2AB^2}\Rightarrow AB\approx4,24\)cm 

\(\Rightarrow AC\approx4,24\sqrt{2}\)cm

Theo định lí Pytago tam giác ABC vuông tại A

\(BC=\sqrt{AB^2+AC^2}\approx\sqrt{4,24^2+\left(4,24\sqrt{2}\right)^2}\approx7,34\)cm