Answer: 240 seconds OR 4 minutes
Step-by-step explanation:
Length of the train = 1 km
Length of the tunnel = 1 km
Therefore, length of the train + length of the tunnel = (1 + 1) km = 2 km
= 2000 m
Speed of the train = 30 km/hr = 8.333 metres per second
Therefore, time taken by the train to cross the tunnel = 2000 m/ 8.333 m/sec.
= 240 seconds = 4 minutes
Answer:
the answer is n=- 18
Step-by-step explanation:
Step-by-step explanation:
or,(x-2)(x-4)+(3x-11)(x-3)/(x-3)(x-4)=(4x+13)/(x+1)
or,x^2-4x-2x+8+3x^2-9x-11x+33/x^2-4x-3x+12=(4x+13)/(x+1)
or,4x^2-4x-2x-9x-11x+8+33/x^2-7x+12=(4x+13)/(x+1)
or,4x^2-26x+41/x^2-7x+12=(4x+13)/(x+1)
or, (x+1)(4x^2-26x+41)=(4x+13)(x^2-7x+12)
or,4x^3-26x^2+41x+4x^2-26x+41=4x^3-28x^2+48x+13x^2-91x+156
or,-26x^2+4x^2+28x^2-13x^2+41x-26x-48x+91x=156-41
or,-7x^2+58x=115
or,-7x^2+58x-115=0
or,-(7x^2-58x+115)=0
or,7x^2-58x+115=0
or,7x^2-(35+23)x+115=0
or,7x^2-35x-23x+115=0
or,7x (x-5)-23 (x-5)=0
or, (x-5)(7x-23)=0
Either, Or,
(x-5)=0 (7x-23)=0
or,x=0+5 or,7x=23
:x=5 :x=23/7
Hence,x=5 or 23/7
Answer: B. 12 girls
Step-by-step explanation:
Since the ratio is 4:3 we can multiply both sides by 4 to get 16 boys and the equivalent number of girls for this problem, 16:12
when two numbers have the same variable, we can add and subtract just like normal numbers.
12x + 8x = 20x - 3x = 17x