0580 Mathematics doubt

[Achmerd]

I have a doubt...pls need HELP!!! this is the question... i donno how to do these questions. its very difficult for me to understand.. so can any one explain this to me (with workings) pls pls...

1 (a) The scale of a map is 1:20 000 000.
On the map, the distance between Cairo and Addis Ababa is 12 cm.

(i) Calculate the distance, in kilometres, between Cairo and Addis Ababa.

Answer (a)(i) ________________km[2]

(ii) On the map the area of a desert region is 13 square centimetres.
Calculate the actual area of this desert region, in square kilometres.
Answer (a)(ii)________________ km2 [2]

(b) (i) The actual distance between Cairo and Khartoum is 1580 km.
On a different map this distance is represented by 31.6 cm.
Calculate, in the form 1 : n, the scale of this map.
Answer (b)(i) 1 : ____ [2]

(ii) A plane flies the 1580 km from Cairo to Khartoum.
It departs from Cairo at 11 55 and arrives in Khartoum at 14 03.
Calculate the average speed of the plane, in kilometres per hour.
Answer (b)(ii) ________________km/h [4]

 

[Iridescent]

1.a. (i) as 1cm represents 20000000cm, the distance is 12 multiplied by 20000000cm.
=240000000cm =2400km.

(ii) The area on the map is 13 square centimeters. 1 square cm actually will be (square of 20000000) which is 400000000000000 square cm, which is equal to 4000 square km.

(b) (i) The actual distance is 1580. Therefore on the map, it will be 1580 divided by 20000000, which is equal to 0.000079cm.
On a different map this distance is represented by 31.6 cm. Ratio= 0.000079:31.6 which is 1:400000.

(ii) Average speed= Total Distance divided by Time Taken.
Distance= 1580 km.
Time= 2 hours 8 min. =2.13 hours.
answer= 1580 divided by 2.13 =741.8 km/h.

 

[Achmerd]

Thanks duaazahra!!

 

[Achmerd]

http://www.xtremepapers.com/CIE/Cambrid ... _qp_22.pdf

Question 6 and 18.. help me to solve it... plspls

 

[Iridescent]

Q6: in (2*2) matrix, the determinant is found by mutiplying the first term with last one and from it subtract the socnd term multiplied by third one.
in ur question,
the determinant of A can be found as
(0*-12)-(-4*1)
= 4
determinant of B= (3*-4)-(0*4)
=-12
now 5|A|+|B|= 5(4) + (-12)
=20-12
=8.
im still confusd bout da 18 one will confirm it first.