Mathematics MCQs

Downstream speed is 15 km/h and upstream speed is 10 km/h.
Still-water speed is their average: 12.5 km/h.

Substitute x = 2 to obtain 4 + 3y = 13.
Then 3y = 9, so y = 3.

Each term is multiplied by 2.
Thus, 24 × 2 = 48.

Their daily rate is 1/16 + 1/24 = 5/48.
In 4 days they do 5/12, so 7/12 remains.

Speed equals distance divided by time.
Thus, 180 ÷ 3 = 60 km/h.

In the same time, the faster runner covers 1,000 m while the slower covers 900 m.
Their speed ratio is therefore 1,000:900 = 10:9.

The expression is a difference of squares: x² - 3².
Thus, it factors as (x - 3)(x + 3).

Dividing 84 by primes gives 84 = 2 × 2 × 3 × 7.
This is 2² × 3 × 7.

The decimal 0.375 equals 375/1000.
Dividing numerator and denominator by 125 gives 3/8.

One third of 3/4 is 1/4 of the full tank.
The remaining amount is 3/4 - 1/4 = 1/2.

The total ratio parts are 7, so one part is 35/7 = 5 liters.
Water is two parts, or 10 liters.

The discount is 15% of Rs. 2,000, which is Rs. 300.
The sale price is Rs. 2,000 - Rs. 300 = Rs. 1,700.