A) 18 | B) 36 |

C) 45 | D) None of these |

Explanation:

Let R, G and B represent the number of balls in red, green and blue boxes respectively.

Then,

R + G + B = 108 ...(i),

G + R = 2B ...(ii)

B = 2R ...(iii)

From (ii) and (iii), we have G + R = 2x 2R = 4R or G = 3R.

Putting G = 3R and B = 2R in (i), we get:

R + 3R + 2R = 108 6R = 108 R = 18.

Therefore Number of balls in green box = G = 3R = (3 x 18) = 54.

A) 12 & 7 | B) 13 & 8 |

C) 15 & 10 | D) 14 & 9 |

A) 6 | B) 9 |

C) 7 | D) 5 |

Explanation:

Arithmatic mean = sum/members

=> (1x1 + 2x2 + 3x3 + 4x4 + 5x5 + 6x6 + 7x7) / (1 + 2 + 3 + 4 + 5 + 6 + 7)

=> 140/28 = 5

A) 5 | B) 4 |

C) 7 | D) 6 |

Explanation:

Let the number be x. Then,

- 4x = x + 50

- 5x - 50 = 0

(3x + 10)(x - 5) = 0

x = 5

A) 30 | B) 27 |

C) 23 | D) 33 |

Explanation:

Then, A:B = 2:3 and B:C = 5:8

= (5 x 3/5) : (8 x 3/5) = 3:24/5

A:B:C = 2:3:24/5

= 10:15:24 => B = 98 x 15/49 = 30.

A) 4 | B) 10 |

C) 8 | D) 5 |

Explanation:

If Vijay gives 'x' marbles to Ajay then Vijay and Ajay would have V - x and A + x marbles.

V - x = A + x --- (1)

If Ajay gives 2x marbles to Vijay then Ajay and Vijay would have A - 2x and V + 2x marbles.

V + 2x - (A - 2x) = 30 => V - A + 4x = 30 --- (2)

From (1) we have V - A = 2x

Substituting V - A = 2x in (2)

6x = 30 => x = 5.