Question

a hostel canteen requires 42 kg of rice for a week. how much quantity of rice is needed for 20 days?

Please give a step by step explanation ASAP​

Answer 1

Answer:

A plate of mass M is held in air by firing bullets each of mass m with same velocity in vertically upward direction. If n bullets are fired per minute and each bullet strikes the plate with speed v and rebounds with half of the speed with which it strikes the plate, then the speed with which bullets are striking the plate is [Take g as acceleration due to gravity] ___________.

(a) \frac{40Mg}{mn}mn40Mg

(b) \frac{2Mg}{3mn}3mn2Mg

(c) \frac{120Mg}{nm}nm120Mg

(d) \frac{Mg}{20nm}20nmMg

From: ANTHE 2020 Mock Test Paper. (Class IXth Physics.)

Answer 2

$\huge\fbox\green{ \fbox\orange{Solutions:-}}$

$\fbox\red{ \fbox\pink{To find:-}}$

$\green{quantity \: of \: rice \: required \: for \: 20 \: days}$

$\fbox\red{ \fbox\red{By the problem:-}}$

$\blue{for \: 7 \: days \: rice \: required = 42g} \\ \green{for \: 1 \: days \: rice \: required = (\frac{42}{7})g } \\ \orange{for \: 20 \: days \: rice \: required = (\frac{42 \times 20}{7} )g} \\ = \pink{120g}$

$\fbox\red{ \fbox\blue{Answer:-}}$

$\blue{120g}$

$\fbox\red{ \fbox\pink{Conclusion:-}}$

$\purple{It \: is \: solved \: by \: unitary \: method.}$

$\purple{1 \: week= \: 7\: days}$