Question

The least multiply of 7 which leave a remainder of 4 , when divided by 6, 9, 15 and 18 is --------​

Answer 1

$\begin{lgathered}\large\underline{\underline{\mathfrak{\color{green}{given :-}}}} \\\end{lgathered}$

An aeroplane flies 200km .

a uniform speed of 300km/h .

then another 200km .

a uniform speed of 240km/h.

$\begin{lgathered}\large\underline{\underline{\mathfrak{\color{blue}{To \: Find :-}}}} \\\end{lgathered}$the average speed of the aeroplane.

$\begin{lgathered}\large\underline{\underline{\mathfrak{\color{red}{Solution :-}}}} \\\end{lgathered}$

total distance = 200 + 200

total distance = 400 km

time taken for first 200 km

$\begin{lgathered}\sf \to \: \frac{200}{300} \\\\ \sf \to \: \frac{2}{3}\end{lgathered}$

$\begin{lgathered}\sf \to \: \frac{200}{240} \\\\ \sf \to \: \frac{5}{6}\end{lgathered}$

$\begin{lgathered}\sf \to \: \frac{2}{3}+\: \frac{5}{6} \\\\ \sf \to \: \frac{9}{6}\\\\\sf\to 1.5\end{lgathered}$

$\begin{lgathered}\sf average \: speed \: = \frac{total \: distance}{total \: time} \\ \\\end{lgathered}$

$\begin{lgathered}\sf \to \: \frac{400}{1.5} \\ \\ \sf \to \: \frac{800}{3} \\ \\ \sf \to \red{ 266.67kmph} \:\end{lgathered}$

Answer 2

Answers:

364

Step-by-step explanation:

L.C.M. of 6, 9, 15 and 18 is 90.

Let required number be 90k + 4, which is multiple of 7.

Least value of k for which (90k + 4) is divisible by 7 is k = 4.

Required number = (90 x 4) + 4 = 364.