Questions

Gitanjali Rao, an 11-year-old Indian-American schoolgirl, was named as "America’s top young scientist" for inventing a cost-effective, quick lead-contamination detector in water. The seventh-grade student was inspired by the large-scale lead contamination in water in Flint, Michigan, that came to light recently.

The 'Parents’ Worship Day' (or 'Matru-Pitru Diwas' ) is celebrated every year by the Chhattisgarh government on February 14 at all schools in the state to teach 'Bharatiya sanskriti' to students.

Scientists estimate the volume of blood in a human body to be approximately 7 percent of body weight. An average adult body with a weight of 150 to 180 pounds will contain approximately 4.7 to 5.5 liters of blood. An average child with a body weight of 80 pounds will have approximately half the amount of blood as an adult.

The amount of blood in a human body varies, depending on factors such as age, sex, overall health and even where a person lives. For example, men tend to have more blood than women of comparable size and weight.

Interestingly, people who live at high altitudes may have up to two liters of extra blood compared to those who live at lower altitudes. Because the air at higher altitudes has less oxygen, people who live at high altitudes need extra blood to deliver the right amount of oxygen to their lungs.

We know that 1 Pint = 0.473 liters

Hence, an average amount of blood in the human body = 4.7 - 5.5 lit = 10 - 12 pints.

Let length and breadth of rectangle be L cm
and B cm respectively So, ATQ
Area1= (L-6)×B
But this is square, so L-6=B
Area1= (L-6) × (L-6)
Case 2, Area2= L × (B+6),
L=B+6
So, Area2= L × L,
Given, Area2-Area1= 252(L)2-(L-6)2=252
Solving this, L= 24
B= 18
Perimeter= 2(L+B)= 2(24+18)= 84 cm

Anything that has Mass and takes up Space is called Matter.

Matter has some mass and occupies some space. Mass means the amount of matter in an object. Space occupied by an object is called its Volume.

The Study of Matter and and how matter changes is called Chemistry.