( c ) At ( ) � 800 ( M1 ) for setting equation
0.3t 240e � 800
0.3t
240 800 0
e � � ( A1 ) for correct approach By considering the graph of t � 4.0132427 . �It takes 4.01 months . y� � ,
0.3t
240e
800
( d ) B( 10 ) � 1000 ( M1 ) for setting equation
10k 360e � 1000
10k
360 1000 0
e � � ( A1 ) for correct approach By considering the graph of y� � ,
10k
360e
1000
|
k � 0.1021651
.
|
|
�k �
0.102
|
A1 |
|
|
[ 3 ] |
( e ) |
A( t) � B( t) |
( M1 ) for setting inequality |
A( t) �B( t) � 0
0.3t
0.1021651 t
240e
360e
0
A1
� � A1 By considering the graph of y e e
0.3 0.1021651
240 t t
� � 360 , 2.0495125 t � . ( A1 ) for correct approach
�n � 3
A1
[ 3 ]
[ 4 ]
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