Explanation

The pattern of the sequence is doubling the previous term:

• 10 × 2 = 20
• 20 × 2 = 40
• 40 × 2 = 80
• 80 × 2 = 160

So, the next number in the sequence is 160.

Explanation

You (the husband)

Your wife

Two sons

Each son has one sister, which means there is one daughter (not two, as both sons share the same sister)

So, the family consists of:

2 parents (you and your wife)

2 sons

1 daughter

Adding them up:2+2+1=5

Explanation

"Father of my brother" refers to Abdul's father.

"Only daughter of the father" refers to Abdul's sister (since Abdul's father has only one daughter).

"He is the son of..." refers to Anwar being the son of Abdul's sister.

Therefore, Abdul is Anwar's:

Maternal Uncle

Explanation

• X does not have any sons or brothers but Y’s father is X’s father-son. Daughter is Y to X
• ***
  
  
• Y term is used here as female.
• X is a boy and Y is a girl.
• X does not have a son or brother.
• Y’s father and X are the same people.
• Therefore, Y is the daughter of X.

Explanation

C is the wife of D and D is the son of A.

Hence,

A is either father-in-law or mother-in-law.

Explanation

 Semiconductors, like silicon and germanium, are substances whose electrical conductivity lies between that of conductors (such as metals) and insulators (such as rubber).

Their ability to conduct electricity under specific conditions,

Along with their moderate conductivity and the possibility to vary their properties

Makes them essential for modern electronic components like diodes and transistors. 

Explanation

Semi-conductors like germanium and silicon are tetravalent. 

"Tetravalent" means they have four valence electrons, which is the key characteristic of semiconductor elements. 

Pentavalent: This means having five valence electrons.

Trivalent: This means having three valence electrons.

Divalent: This means having two valence electrons.

Explanation

 Silicon is the second most abundant element in the Earth's crust,

Making up a large portion of most rocks and minerals, particularly silicates, which are composed of silicon and oxygen. 

Earth's Crust Elements

1 Oxygen (O) 46.1%

2 Silicon (Si) 28.2%

3 Aluminum (Al) 8.2%

4 Iron (Fe) 5.6%

Explanation

The body is covered by a glandular epithelial envelope called a mantle

They secrete a calcareous shell

Explanation

The two most common elements in the Earth's crust are:

• Oxygen (O) – about 46.6% by weight
• Silicon (Si) – about 27.7% by weight

Together, they form most of the silicate minerals, which make up the majority of the crust. 

Last updated 14-feb-2026