Shenzhen o-film tech co., ltd. Interview Questions, Process, and Tips

12.5

1/24+1/30+1/40=1/10 => 10 days
4/10 = 0.4
1/(24*0.4)+1/(30*0.4) = 0.1875 => 5.33

(10-4) + 5.33 = 11.3 days

let MP = 100x
25% discount = 75x -> SP
Profit% = (Profit/CP)x100
125 = (75x/CP)x100
.: CP = 60x

Now if discount = 10%
SP = 90x
.: Profit% = ((90x-60x)/60x)x100 = 50%

17.9

If n = no. of revolutions for back wheel
9n = 7n + 10*7
n=315

First write equations from info:
(A) (Mon + Tue + Wed)/3 = 111 Rearrange as ——–> Tue + Wed = 111 – Mon
(B) (Tue + Wed + Thu)/3 =102 Rearrange as ——–> Tue + Wed = 102 – Thu
(C) Thu = 0.8(Mon)

Substitute equation C into B:
(B) Tue + Wed = 102 – 0.8(Mon)

At this point I changed the values for clearer algebra:
Mon = x
Tue + Wed = y

Re-write equations A & B with new values:
(A) y = 111 – x
(B) y = 102 – 0.8x

Solve simultaneous equations:

111 – x = 102 – 0.8x
111 – 102 = x – 0.8x (Re-arraged)
9 = 0.2x
x = 45

Thus, Mon = 45C

Thu = 0.8(45)
Thu = 36C

So the answer is it was 36C on Thursday

Three families

4/5

but how?

c

48,400

Turn on a switch and leave it for some ten minutes. Turn it off, turn a second one on and open the door and go into the room. The glowing bulb corresponds to second switch. The bulb that is hot corresponds to first switch, as it was turned on for ten minutes and have heated up. The cold and not-glowing bulb corresponds to the third switch

15

5 * 6 * 7 = 210 ,
Two Least No’s are 5,6
There fore 5+6=11 is answer

160600