Maths

30minutes=0.5hour
After 30minutes, car A has gone: 40*0.5=20km
car B needs:(60-40)/20=1hour


OR


let car B needs x hour to catch up with car A
40*0.5+40x=60x
20+40x=60x
20=20x
x=1
So car B needs 1 hour to catch up with car A

上門補習:
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上門補習:
名校中學畢業
學業成績曾試過在全班頭三名之內
教授 DSE 文憑數學 ( 基本課程，M1，M2）
每堂$ 500 (45-60 min)
第一，二堂(試堂) $0 . 免費 （只限兩堂，如試堂不適合可以不上第三堂 ）
詢問可電62806183

Maths




The speed of car A and B are 40km/h and 60 km/h respectively.
If car A starts 30 minutes before car B. How long will it take so that catches up with car A ?

answer:
40×0.5÷(60-40)
＝20÷20
＝1


40*0.5(30minutes later car A 20 meters away
CAR A and B rate

1 hr!!!!!!!!!!