a;  \(\dfrac{5}{7}\) + \(\dfrac{7}{13}\) + \(\dfrac{19}{13}\) + \(\dfrac{6}{5}\) + \(\dfrac{9}{7}\) 

= (\(\dfrac{5}{7}\) + \(\dfrac{9}{7}\)) + (\(\dfrac{7}{13}\) + \(\dfrac{19}{13}\)) + \(\dfrac{6}{5}\)

= 2 + 2 + \(\dfrac{6}{5}\)

= 4 + \(\dfrac{6}{5}\)

= \(\dfrac{26}{5}\)

\

b; 576 + 789 + 467 + 111

= (789 + 111) + (576 + 424) + 43

= 900 + 1000 + 43

= 1900 + 43

= 1943 

        Giải:

 2 giờ 30 phút = 2,5 giờ

Quãng đường AB dài là: 60,8 x 2,5 = 152 (km)

Thời gian ô tô đi từ B về A là:

  152 : 50 = 3,04 (giờ)

3,04 giờ = 3 giờ 2phút 24 giây 

Kết luận:..

Q

a: Ta có: QN\(\perp\)MP(MNPQ là hình vuông)

QN\(\perp\)MS(SM\(\perp\)(MNPQ))

MP,MS cùng thuộc mp(SMP)

Do đó: QN\(\perp\)(SMP)

Bạn muốn hỏi gì?

???

The number of numbers from 35 to 69 is divisible by 4 is:

(68 - 36) : 4 + 1 = 9 (numbers)

The number of numbers not divisible by 4 is:

35 - 9 = 26 (numbers)

There is at least a number of randomly drawn numbers from 35 to 69 to ensure that there are 2 numbers divisible by 4 is:

26 + 2 = 28 (numbers)

There are two numbers whose product is divisible by 4 when it has 01 number which is divisible by 4 or both of two are even number. So,

In the worst scenario, we have:

18 odd numbers that cannot create pair of numbers

Drawn 01 even number but it is not divisible by 4

In the end, we drawn 01 even number.Now, we ensure that there are two numbers whose product is divisible by 4

Ø  In result, we at least drawn 20 numbers at random to ensure that there are two numbers whose product is divisible by 4

Câu 3:

\(\dfrac{3}{8}\) - (\(x-\dfrac{1}{4}\)) = \(\dfrac{3}{16}\)

        \(x-\dfrac{1}{4}\)  = \(\dfrac{3}{8}\) - \(\dfrac{3}{16}\)

        \(x-\dfrac{1}{4}=\dfrac{3}{16}\)

         \(x\) = \(\dfrac{3}{16}\) + \(\dfrac{1}{4}\)

         \(x=\dfrac{7}{16}\)

Đây phải là môn Giáo Dục Công Dân mà bạn?

trong đó ko có giáo dục công dân bạn