A) 36 kmph | B) 32 kmph |

C) 28 kmph | D) 34 kmph |

Explanation:

Let the speed of goods truck be 'p' kmph

Distance covered by goods truck in 10hrs (4+6) = Distance covered by other truck in 4 hrs.

10p = 4 x 90

p = 36kmph.

Therefore, the speed of the goods truck is p = 36 kmph.

A) 40 | B) 50 |

C) 60 | D) 70 |

Explanation:

Sony and her brother's age sum is 31

Let Sony's mother's age be 'x'.

Now the conditions given for both of their ages related to their mom is

1/5(x-15) + 3/5(x-10) = 31

x-15 + 3x-30 = 155

4x-45 = 155

4x = 200

x = 50

So, Mother's age = 50.

Cross verification : 15 years ago age = 35 => Sony age = 7

10 years ago age = 40 => bro age = 24

Sum = 24 + 7 = 31.

A) 1 | B) 2 |

C) 3 | D) 4 |

Explanation:

Given that

So x - 2 =

Now cubing on both sides, we get

=>

=> .

Therefore, = 2.

A) 39 days | B) 37 days |

C) 35 days | D) 33 days |

Explanation:

Distance d = 1200km

let S be the speed

he walks 15 hours a day(i.e 24 - 9)

so totally he walks for 70 x 15 = 1050hrs.

S = 1200/1050 => 120/105 = 24/21 => 8/7kmph

given 1 1/2 of previous speed

so 3/2 * 8/7= 24/14 = 12/7

New speed = 12/7kmph

Now he rests 10 hrs a day that means he walks 14 hrs a day.

time = 840 x 7 /12 => 490 hrs

=> 490/14 = 35 days

So he will take 35 days to cover 840 km.