The ratio of the amount of work done by (x-1) labours in (x+1) days and that done by (x+1) labours in (x+2) days is 5 : 6. Then the value of x is

A can do as much work in 4 days as B can do in 5, and B can do as much work in 6 days as C in 7. In what time will C do a piece of work which A can do in a week ?

Ramesh and Rahman can do a work in 20 and 25 days respectively. After doing collectively 10 days of work, they leave the work due to illness and Suresh completes rest of the work in 3 days. How many days Suresh alone can take to complete the whole work ?

Simplify : -21973 × -1253 ÷ 275123

The sum of three numbers is 252. If the first number is thrice the second and third number is two-third of the first, then the second number is

A number when divided by the sum of 555 and 445 gives two times their difference as quotient and 30 as the remainder. The number is

Each member of a club contributes as much rupees and as much paise as the number of members of the club. If the total contribution is Rs. 2525, then the number of members of the club is

A passage is given with 5 questions following it. Read the passage carefully and choose the best answer to each question out of the four alternatives.

The quest to find life outside the solar system got a big boost with the discovery of seven Earth-size extra-solar planets, or exoplanets, orbiting a dwarf star about 40 light years away. Unlike earlier discoveries of exoplanets, all seven planets could possibly have liquid water — a key to life as we know it on Earth — with three planets having the greatest chance. This is by far the largest collection of Earth-like planets in the habitable 'Goldilocks' zone of a star — neither too close nor too far from a star, which raises the possibility of liquid water being present on the surface. Only Earth has liquid water in the solar system. Since the dwarf star is much cooler than the Sun, the dimming of light each time a planet passes or transits before the star could be easily recorded from Earth unlike in cases when planets transit a Sun-like bright star. Since the initial discovery of three planets was made using the Chile-based Transiting Planets and Planetesimals Small Telescope, the exoplanet system is called TRAPPIST-1.

How many planets in our solar system have liquid water?