Beginning with T1 at the hand, the rope enters and exits the first pulley with T1.  Label these values.  However, you cannot label the value at the eye of the pulley until you know the T value of the carabiner connected to the bottom becket on this first pulley.

The rope then enters and exits the bottom red pulley with T1.  Again, you cannot write down the value at the eye of this pulley until you know the force of the carabiner connected to the becket.

The rope then enters and exits the smaller red pulley with the same T1. This pulley also has a becket.

The rope then enters and exits the smaller blue pulley with T1. You can label the eye of this pulley T2.

The rope then terminates with the knot on the small red pulley's becket. The rope at this point the rope has the T1 that existed when the rope exited the blue pulley. This is illustrated by the arrow on Figure 1.

The T values that you can record up to this point are show in Figure 1.

Figure 1

Now that you know that the becket on the bottom of the small red pulley is T1, you can label the eye of this pulley T3. This is the sum of the T1s on either side of the pulley plus the T1 on the becket.

Similarly, you can label the eye of the upper red pulley as T5. This is the sum of the T1s on either side of the pulley plus the T3 on the becket.

You know that the becket on on the bottom red pulley is receiving T2 from the blue pulley.  This T2 plus the T1s on either side of the bottom red pulley is T4, which applies to the eye of the bottom red pulley and the load.

These T values are all shown in Figure 2. Since there is T1 on the hand and T4 on the pulley, this is a 4-to-1 (i.e., 4:1) system.

Each one pound of pull by the hand will raise 4 pounds of load.  This hand is holding 25 pounds of the 100 pound load.

Note that the anchor is holding 125 pounds (i.e., T5).  This is the 100 pound load plus the 25 pounds that the hand is pulling against the anchors.

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